1.
Wedge prism
–
The wedge prism is a prism with a shallow angle between its input and output surfaces. This angle is usually 3 degrees or less, refraction at the surfaces causes the prism to deflect light by a fixed angle. When viewing a scene through such a prism, objects appear to be offset by an amount that varies with their distance from the prism. The term optical wedge refers to any angle between two plane surfaces of a window. This wedge may range from a few millionths of a degree of parallelism to as much as three degrees of angle. Even though high-precision optics, such as flats, may be lapped and polished to extremely high levels of parallelism. This margin of error is usually listed in minutes or seconds of arc, windows manufactured with an intentional wedge are often referred to as wedge prisms, and typically come with wedge angles of one, two, or three degrees. Many applications exist for wedge prisms, including steering, rangefinding. A pair of prisms, called a Risley prism pair. In this case, rotating one wedge in relation to the other will change the direction of the beam, when the wedges angle in the same direction, the angle of the refracted beam becomes greater. When the wedges are rotated to angle in opposite directions, they cancel each other out, moving a wedge either closer or farther away from the laser can also be used to steer the beam. When the wedge is moved closer to the target, the beam will move across the target. This method is common in aerial or space launch-vehicle photography, when the distance to the object is changing very rapidly, wedges were sometimes used in rangefinding, by combining the image formed by one telescope with the image formed by another. The wedge prism is used in a similar manner as an angle gauge in variable-radius plot sampling. In this type of sampling, the prism is used to estimate basal area of a group of trees by counting trees which are in or out of a plot centered on a single point. A tree is an in tree if the section of the tree overlaps the bole as viewed without the prism. A tree where the section of the trunk is perfectly aligned with the original bole is a borderline tree. A tree where the section of the tree does not overlap or touch the original bole is an out tree and is not counted
Wedge prism
–
Figure 1. View through 10 factor wedge prism of an "IN" tree.
Wedge prism
–
Figure 2. View through 10 factor wedge prism of a "Borderline" tree.
Wedge prism
–
Figure 3. View through 10 factor wedge prism of an "OUT" tree.
2.
Optics
–
Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light, because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for using the classical description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice, practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines, physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics. Historically, the model of light was developed first, followed by the wave model of light. Progress in electromagnetic theory in the 19th century led to the discovery that waves were in fact electromagnetic radiation. Some phenomena depend on the fact that light has both wave-like and particle-like properties, explanation of these effects requires quantum mechanics. When considering lights particle-like properties, the light is modelled as a collection of particles called photons, quantum optics deals with the application of quantum mechanics to optical systems. Optical science is relevant to and studied in many related disciplines including astronomy, various engineering fields, photography, practical applications of optics are found in a variety of technologies and everyday objects, including mirrors, lenses, telescopes, microscopes, lasers, and fibre optics. Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, the earliest known lenses, made from polished crystal, often quartz, date from as early as 700 BC for Assyrian lenses such as the Layard/Nimrud lens. The ancient Romans and Greeks filled glass spheres with water to make lenses, the word optics comes from the ancient Greek word ὀπτική, meaning appearance, look. Greek philosophy on optics broke down into two opposing theories on how vision worked, the theory and the emission theory. The intro-mission approach saw vision as coming from objects casting off copies of themselves that were captured by the eye, plato first articulated the emission theory, the idea that visual perception is accomplished by rays emitted by the eyes. He also commented on the parity reversal of mirrors in Timaeus, some hundred years later, Euclid wrote a treatise entitled Optics where he linked vision to geometry, creating geometrical optics. Ptolemy, in his treatise Optics, held a theory of vision, the rays from the eye formed a cone, the vertex being within the eye. The rays were sensitive, and conveyed back to the observer’s intellect about the distance. He summarised much of Euclid and went on to describe a way to measure the angle of refraction, during the Middle Ages, Greek ideas about optics were resurrected and extended by writers in the Muslim world
Optics
–
Optics includes study of
dispersion of light.
Optics
–
The Nimrud lens
Optics
–
Reproduction of a page of
Ibn Sahl 's manuscript showing his knowledge of the law of refraction, now known as
Snell's law
Optics
–
Cover of the first edition of Newton's Opticks
3.
Prism
–
In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the surfaces must have an angle between them. The exact angles between the surfaces depend on the application, the traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use prism usually refers to this type. Some types of optical prism are not in fact in the shape of geometric prisms, prisms can be made from any material that is transparent to the wavelengths for which they are designed. Typical materials include glass, plastic and fluorite, a dispersive prism can be used to break light up into its constituent spectral colors. Furthermore, prisms can be used to light, or to split light into components with different polarizations. Light changes speed as it moves from one medium to another and this speed change causes the light to be refracted and to enter the new medium at a different angle. The degree of bending of the lights path depends on the angle that the incident beam of light makes with the surface, the refractive index of many materials varies with the wavelength or color of the light used, a phenomenon known as dispersion. This causes light of different colors to be refracted differently and to leave the prism at different angles and this can be used to separate a beam of white light into its constituent spectrum of colors. Prisms will generally disperse light over a larger frequency bandwidth than diffraction gratings. Furthermore, prisms do not suffer from complications arising from overlapping spectral orders, prisms are sometimes used for the internal reflection at the surfaces rather than for dispersion. If light inside the prism hits one of the surfaces at a steep angle, total internal reflection occurs. This makes a prism a useful substitute for a mirror in some situations, ray angle deviation and dispersion through a prism can be determined by tracing a sample ray through the element and using Snells law at each interface. For the prism shown at right, the angles are given by θ0 ′ = arcsin θ1 = α − θ0 ′ θ1 ′ = arcsin θ2 = θ1 ′ − α. All angles are positive in the shown in the image. For a prism in air n 0 = n 2 ≃1 and this allows the nonlinear equation in the deviation angle δ to be approximated by δ ≈ θ0 − α + = θ0 − α + n α − θ0 = α. The deviation angle depends on wavelength through n, so for a thin prism the deviation angle varies with wavelength according to δ ≈ α, before Isaac Newton, it was believed that white light was colorless, and that the prism itself produced the color. It was only later that Young and Fresnel combined Newtons particle theory with Huygens wave theory to show that color is the manifestation of lights wavelength
Prism
–
A plastic prism
Prism
–
A triangular prism, dispersing light
4.
Triangular prism
–
In geometry, a triangular prism is a three-sided prism, it is a polyhedron made of a triangular base, a translated copy, and 3 faces joining corresponding sides. A right triangular prism has rectangular sides, otherwise it is oblique, a uniform triangular prism is a right triangular prism with equilateral bases, and square sides. Equivalently, it is a polyhedron of which two faces are parallel, while the normals of the other three are in the same plane. All cross-sections parallel to the faces are the same triangle. A right triangular prism is semiregular or, more generally, a uniform if the base faces are equilateral triangles. It can be seen as a truncated trigonal hosohedron, represented by Schläfli symbol t, alternately it can be seen as the Cartesian product of a triangle and a line segment, and represented by the product x. The dual of a prism is a triangular bipyramid. The symmetry group of a right 3-sided prism with triangular base is D3h of order 12, the rotation group is D3 of order 6. The symmetry group does not contain inversion, the volume of any prism is the product of the area of the base and the distance between the two bases. A truncated right triangular prism has one triangular face truncated at an oblique angle, there are two full D2h symmetry facetings of a triangular prism, both with 6 isosceles triangle faces, one keeping the original top and bottom triangles, and one the original squares. Two lower C3v symmetry faceting have one triangle,3 lateral crossed square faces. This polyhedron is topologically related as a part of sequence of uniform truncated polyhedra with vertex configurations and this polyhedron is topologically related as a part of sequence of cantellated polyhedra with vertex figure, and continues as tilings of the hyperbolic plane. These vertex-transitive figures have reflectional symmetry and this polyhedron is topologically related as a part of sequence of cantellated polyhedra with vertex figure, and continues as tilings of the hyperbolic plane. These vertex-transitive figures have reflectional symmetry, there are 4 uniform compounds of triangular prisms, Compound of four triangular prisms, compound of eight triangular prisms, compound of ten triangular prisms, compound of twenty triangular prisms. Each progressive uniform polytope is constructed vertex figure of the previous polytope, thorold Gosset identified this series in 1900 as containing all regular polytope facets, containing all simplexes and orthoplexes. In Coxeters notation the triangular prism is given the symbol −121, the triangular prism exists as cells of a number of four-dimensional uniform 4-polytopes, including, Wedge Weisstein, Eric W. Triangular prism. Interactive Polyhedron, Triangular Prism surface area and volume of a triangular prism
Triangular prism
–
Uniform Triangular prism
5.
Dispersion (optics)
–
In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Media having this property may be termed dispersive media. Sometimes the term chromatic dispersion is used for specificity, the most familiar example of dispersion is probably a rainbow, in which dispersion causes the spatial separation of a white light into components of different wavelengths. Most often, chromatic dispersion refers to material dispersion, that is. However, in a waveguide there is also the phenomenon of waveguide dispersion, more generally, waveguide dispersion can occur for waves propagating through any inhomogeneous structure, whether or not the waves are confined to some region. In a waveguide, both types of dispersion will generally be present, although they are not strictly additive, for example, in fiber optics the material and waveguide dispersion can effectively cancel each other out to produce a zero-dispersion wavelength, important for fast fiber-optic communication. Material dispersion can be a desirable or undesirable effect in optical applications, the dispersion of light by glass prisms is used to construct spectrometers and spectroradiometers. Holographic gratings are used, as they allow more accurate discrimination of wavelengths. However, in lenses, dispersion causes chromatic aberration, an effect that may degrade images in microscopes, telescopes. The phase velocity, v, of a wave in a uniform medium is given by v = c n where c is the speed of light in a vacuum. In general, the index is some function of the frequency f of the light, thus n = n, or alternatively. The wavelength dependence of a refractive index is usually quantified by its Abbe number or its coefficients in an empirical formula such as the Cauchy or Sellmeier equations. In particular, for materials, the susceptibility χ that appears in the Kramers–Kronig relations is the electric susceptibility χe = n2 −1. The most commonly seen consequence of dispersion in optics is the separation of light into a color spectrum by a prism. From Snells law it can be seen that the angle of refraction of light in a prism depends on the index of the prism material. For visible light, refraction indices n of most transparent materials decrease with increasing wavelength λ,1 < n < n < n, or alternatively, in this case, the medium is said to have normal dispersion. Whereas, if the index increases with increasing wavelength, the medium is said to have anomalous dispersion, at the interface of such a material with air or vacuum, Snells law predicts that light incident at an angle θ to the normal will be refracted at an angle arcsin. Thus, blue light, with a refractive index, will be bent more strongly than red light
Dispersion (optics)
–
A
compact fluorescent lamp seen through an
Amici prism
Dispersion (optics)
–
In a
dispersive prism, material dispersion (a
wavelength -dependent
refractive index) causes different colors to
refract at different angles, splitting white light into a
rainbow.
6.
Spectrum
–
A spectrum is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism, as scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum. Spectrum has since been applied by analogy to topics outside of optics, thus, one might talk about the spectrum of political opinion, or the spectrum of activity of a drug, or the autism spectrum. In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions, such uses imply a broad range of conditions or behaviors grouped together and studied under a single title for ease of discussion. Nonscientific uses of the spectrum are sometimes misleading. For instance, a single left–right spectrum of opinion does not capture the full range of peoples political beliefs. Political scientists use a variety of biaxial and multiaxial systems to accurately characterize political opinion. In most modern usages of spectrum there is a theme between the extremes at either end. This was not always true in older usage, in Latin spectrum means image or apparition, including the meaning spectre. Spectral evidence is testimony about what was done by spectres of persons not present physically and it was used to convict a number of persons of witchcraft at Salem, Massachusetts in the late 17th century. The word spectrum was used to designate a ghostly optical afterimage by Goethe in his Theory of Colors and Schopenhauer in On Vision. The prefix spectro- is used to form words relating to spectra, for example, a spectrometer is a device used to record spectra and spectroscopy is the use of a spectrometer for chemical analysis. In the 17th century the word spectrum was introduced into optics by Isaac Newton, soon the term referred to a plot of light intensity or power as a function of frequency or wavelength, also known as a spectral density plot. The term spectrum was expanded to apply to other waves, such as sound waves that could also be measured as a function of frequency, frequency spectrum and power spectrum of a signal. The term now applies to any signal that can be measured or decomposed along a variable such as energy in electron spectroscopy or mass to charge ratio in mass spectrometry. Spectrum is also used to refer to a representation of the signal as a function of the dependent variable. Devices used to measure an electromagnetic spectrum are called spectrograph or spectrometer, the visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. The wavelength of light ranges from 390 to 700 nm
Spectrum
–
The spectrum in a
rainbow
Spectrum
–
Electromagnetic spectrum of a
quasar.
Spectrum
–
Mass spectrum of
Titan 's
ionosphere
Spectrum
–
Spectrogram of
dolphin vocalizations.
7.
Colors
–
House of Heroes is an alternative rock band from Columbus, Ohio. They have released six albums, What You Want Is Now, House of Heroes, The End Is Not the End, Suburba, Cold Hard Want, and Colors. The band also released the album Ten Months under their name, No Tagbacks. They also re-released their self-titled record under the name of Say No More, the band is composed of Tim Skipper, Colin Rigsby, A. J. The band got started in 1996 at Hilliard Davidson High School, originally as a band called Plan B, with Tim Skipper. Babcock, and Nate Rothacker on drums, in 1998, Colin Rigsby replaced Nate Rothacker on drums and they changed their name to No Tagbacks, then later to House of Heroes. The band recorded demos at Chris Lundquists home studio LundquistAudio. In 2003 they released their first album What You Want Is Now under the name House of Heroes, Jared Rigsby replaced A. J. Babcock as the bands live bassist in December 2005, as Babcock had married and focused on a side project with his wife called FlowerDagger. Babcock eventually rejoined the band as the live bassist and Jared Rigsby became a member as the bands second guitarist. In 2009, Babcock stopped touring for the time and was replaced by Eric Newcomer as the live bassist. After Babcock rejoined the band once more in 2012 as bassist, Newcomer became a member as the bands second guitarist. After only a touring stint in early 2012, Babcock stopped touring again. Jared Rigsby did not appear in the bands In The Studio video for Cold Hard Want, in March 2010 Colin Rigsby was replaced by Josh Dun on drums as Rigsby felt he needed to spend more time with his family. In October 2010 Rigsby resumed drumming duty, according to drummer, Colin Rigsby, some of House of Heroes influences are, The Beatles, Queen, Bruce Springsteen, and The Clash. Tim Skipper also said that Muse is a source of influence, in his free time, Rigsby works on Art, and has his own website. He is currently working with Jon Schneck of Relient K on a novel titled En Carne. Though they are considered to be Christian rock due to their association with Gotee Records. We kind of felt like we should straddle the line, in another interview, bassist AJ Babcock said, We never wanted to try to pander to a Christian audience by saying things that necessarily were just kind of, you know, lip service to people
Colors
–
Colored pencils
8.
Rainbow
–
A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured arc, Rainbows caused by sunlight always appear in the section of sky directly opposite the sun. However, the observer sees only an arc formed by illuminated droplets above the ground. In a primary rainbow, the arc shows red on the outer part and this rainbow is caused by light being refracted when entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it. In a double rainbow, an arc is seen outside the primary arc. A rainbow is not located at a distance from the observer. Thus, a rainbow is not an object and cannot be physically approached, indeed, it is impossible for an observer to see a rainbow from water droplets at any angle other than the customary one of 42 degrees from the direction opposite the light source. Even if an observer sees another observer who seems under or at the end of a rainbow, Rainbows span a continuous spectrum of colours. Rainbows can be caused by many forms of airborne water and these include not only rain, but also mist, spray, and airborne dew. Rainbows can be observed there are water drops in the air. Because of this, rainbows are seen in the western sky during the morning. The most spectacular rainbow displays happen when half the sky is dark with raining clouds. The result is a rainbow that contrasts with the darkened background. During such good visibility conditions, the larger but fainter secondary rainbow is often visible and it appears about 10° outside of the primary rainbow, with inverse order of colours. The rainbow effect is commonly seen near waterfalls or fountains. In addition, the effect can be created by dispersing water droplets into the air during a sunny day. Rarely, a moonbow, lunar rainbow or nighttime rainbow, can be seen on strongly moonlit nights, as human visual perception for colour is poor in low light, moonbows are often perceived to be white. It is difficult to photograph the complete semicircle of a rainbow in one frame, for a 35 mm camera, a wide-angle lens with a focal length of 19 mm or less would be required
Rainbow
–
Double rainbow and supernumerary rainbows on the inside of the primary arc. The shadow of the photographer's head on the bottom marks the centre of the rainbow circle (
antisolar point).
Rainbow
–
Image of the end of a rainbow at
Jasper National Park
Rainbow
–
Rainbows can form in mist, such as that of a waterfall.
Rainbow
–
Rainbow with a faint reflected rainbow in the lake
9.
Refraction
–
Refraction is the change in direction of wave propagation due to a change in its transmission medium. The phenomenon is explained by the conservation of energy and the conservation of momentum, due to the change of medium, the phase velocity of the wave is changed but its frequency remains constant. This is most commonly observed when a wave passes from one medium to another at any other than 0° from the normal. In optics, refraction is a phenomenon that occurs when waves travel from a medium with a given refractive index to a medium with another at an oblique angle. At the boundary between the media, the phase velocity is altered, usually causing a change in direction. Its wavelength increases or decreases, but its frequency remains constant, for example, a light ray will refract as it enters and leaves glass, assuming there is a change in refractive index. A ray traveling along the normal will change speed, but not direction, refraction still occurs in this case. Understanding of this led to the invention of lenses and the refracting telescope. Refraction can be seen looking into a bowl of water. Air has a index of about 1.0003. If a person looks at an object, such as a pencil or straw, which is placed at a slant, partially in the water. This is due to the bending of light rays as they move from the water to the air, once the rays reach the eye, the eye traces them back as straight lines. The lines of sight intersect at a position than where the actual rays originated. This causes the pencil to appear higher and the water to appear shallower than it really is, the depth that the water appears to be when viewed from above is known as the apparent depth. This is an important consideration for spearfishing from the surface because it will make the fish appear to be in a different place. Conversely, an object above the water has a higher apparent height when viewed from below the water, the opposite correction must be made by an archer fish. For small angles of incidence, the ratio of apparent to real depth is the ratio of the indexes of air to that of water. But, as the angle of incidence approaches 90o, the apparent depth approaches zero, albeit reflection increases, the diagram on the right shows an example of refraction in water waves
Refraction
–
Light on air–plexi surface in this experiment undergoes refraction (lower ray) and
reflection (upper ray).
Refraction
–
Refraction in a glass of water. The image is flipped.
Refraction
–
An image of the
Golden Gate Bridge is refracted and bent by many differing three-dimensional drops of water.
Refraction
10.
Refractive index
–
In optics, the refractive index or index of refraction n of a material is a dimensionless number that describes how light propagates through that medium. It is defined as n = c v, where c is the speed of light in vacuum, for example, the refractive index of water is 1.333, meaning that light travels 1.333 times faster in a vacuum than it does in water. The refractive index determines how light is bent, or refracted. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the angle for total internal reflection. This implies that vacuum has a index of 1. The refractive index varies with the wavelength of light and this is called dispersion and causes the splitting of white light into its constituent colors in prisms and rainbows, and chromatic aberration in lenses. Light propagation in absorbing materials can be described using a refractive index. The imaginary part then handles the attenuation, while the real part accounts for refraction, the concept of refractive index is widely used within the full electromagnetic spectrum, from X-rays to radio waves. It can also be used with wave phenomena such as sound, in this case the speed of sound is used instead of that of light and a reference medium other than vacuum must be chosen. Thomas Young was presumably the person who first used, and invented, at the same time he changed this value of refractive power into a single number, instead of the traditional ratio of two numbers. The ratio had the disadvantage of different appearances, newton, who called it the proportion of the sines of incidence and refraction, wrote it as a ratio of two numbers, like 529 to 396. Hauksbee, who called it the ratio of refraction, wrote it as a ratio with a fixed numerator, hutton wrote it as a ratio with a fixed denominator, like 1.3358 to 1. Young did not use a symbol for the index of refraction, in the next years, others started using different symbols, n, m, and µ. For visible light most transparent media have refractive indices between 1 and 2, a few examples are given in the adjacent table. These values are measured at the yellow doublet D-line of sodium, with a wavelength of 589 nanometers, gases at atmospheric pressure have refractive indices close to 1 because of their low density. Almost all solids and liquids have refractive indices above 1.3, aerogel is a very low density solid that can be produced with refractive index in the range from 1.002 to 1.265. Moissanite lies at the end of the range with a refractive index as high as 2.65. Most plastics have refractive indices in the range from 1.3 to 1.7, for infrared light refractive indices can be considerably higher
Refractive index
–
Thomas Young coined the term index of refraction.
Refractive index
–
A
ray of light being
refracted in a plastic block.
Refractive index
–
Diamonds have a very high refractive index of 2.42.
Refractive index
–
A
split-ring resonator array arranged to produce a negative index of refraction for
microwaves.
11.
Max Born
–
Max Born was a German physicist and mathematician who was instrumental in the development of quantum mechanics. He also made contributions to physics and optics and supervised the work of a number of notable physicists in the 1920s and 1930s. Born won the 1954 Nobel Prize in Physics for his research in Quantum Mechanics. He wrote his Ph. D. thesis on the subject of Stability of Elastica in a Plane and Space, in 1905, he began researching special relativity with Minkowski, and subsequently wrote his habilitation thesis on the Thomson model of the atom. In the First World War, after originally being placed as a radio operator, in 1921, Born returned to Göttingen, arranging another chair for his long-time friend and colleague James Franck. Under Born, Göttingen became one of the worlds foremost centres for physics, in 1925, Born and Werner Heisenberg formulated the matrix mechanics representation of quantum mechanics. The following year, he formulated the now-standard interpretation of the probability density function for ψ*ψ in the Schrödinger equation and his influence extended far beyond his own research. Max Delbrück, Siegfried Flügge, Friedrich Hund, Pascual Jordan, Maria Goeppert-Mayer, Lothar Wolfgang Nordheim, Robert Oppenheimer, in January 1933, the Nazi Party came to power in Germany, and Born, who was Jewish, was suspended. Max Born became a naturalised British subject on 31 August 1939 and he remained at Edinburgh until 1952. He retired to Bad Pyrmont, in West Germany, and died in a hospital in Göttingen on 5 January 1970. Max Born was born on 11 December 1882 in Breslau, which at the time of Borns birth was part of the Prussian Province of Silesia in the German Empire and she died when Max was four years old, on 29 August 1886. Max had a sister, Käthe, who was born in 1884, Wolfgang later became Professor of Art History at the City College of New York. Initially educated at the König-Wilhelm-Gymnasium in Breslau, Born entered the University of Breslau in 1901, the German university system allowed students to move easily from one university to another, so he spent summer semesters at Heidelberg University in 1902 and the University of Zurich in 1903. Fellow students at Breslau, Otto Toeplitz and Ernst Hellinger, told Born about the University of Göttingen, at Göttingen he found three renowned mathematicians, Felix Klein, David Hilbert and Hermann Minkowski. Very soon after his arrival, Born formed close ties to the two men. Being class scribe put Born into regular, invaluable contact with Hilbert, Hilbert became Borns mentor after selecting him to be the first to hold the unpaid, semi-official position of assistant. Borns introduction to Minkowski came through Borns stepmother, Bertha, as she knew Minkowski from dancing classes in Königsberg, the introduction netted Born invitations to the Minkowski household for Sunday dinners. In addition, while performing his duties as scribe and assistant, Borns relationship with Klein was more problematic
Max Born
–
Max Born (1882–1970)
Max Born
–
Solvay Conference, 1927. Born is second from the right in the second row, between
Louis de Broglie and
Niels Bohr.
Max Born
–
Born's gravestone in Göttingen is inscribed with the uncertainty principle, which he put on rigid mathematical footing.
12.
Emil Wolf
–
He is also the author of several works on optics. Wolf was born in Prague, Czechoslovakia and he was forced to leave his native country when the Germans invaded, After brief periods in Italy and France, he came to the United Kingdom in 1940. He received his B. Sc. in Mathematics and Physics, between 1951 and 1954 he worked at the University of Edinburgh with Max Born, writing the famous textbook on Optics now usually known simply as Born and Wolf. After a period on the Faculty of the University of Manchester and he is currently the Wilson Professor of Optical Physics at the University of Rochester. He is a naturalized US citizen and he was president of the Optical Society of America in 1978. Wolf now resides in Cloverwood in Pittsford, New York, with his wife and he also predicted a new mechanism that produces redshift and blueshift, that is not due to moving sources, that has subsequently been confirmed experimentally. Technically, he found that two non-Lambertian sources that emit beamed energy, can interact in a way that causes a shift in the spectral lines. The Wolf Effect can produce either redshifts or blueshifts, depending on the point of view. A subsequent 1999 article by Sisir Roy et al. have suggested that the Wolf Effect may explain discordant redshift in certain quasars Ref. Wolf is a well known author in the field of optics. Along with Max Born, he co-wrote Principles of Optics of one of the textbooks of optics commonly known as Born. He also co-authored, along with Leonard Mandel, Optical Coherence and he is the author of Introduction to the Theory of Coherence and Polarization of Light and Selected Works of Emil Wolf with Commentary. He also edits the Progress in Optics series of books since its inception in 1962, frederic Ives Medal of the Optical Society of America Albert A. G. Past presidents of the Optical Society of America Progress in Optics Emil Wolf, home Page at University of Rochester. Principles of Optics, Electromagnetic Theory of Propagation, Interference and Diffraction of Light Sample chapters, Emil Wolf at the Mathematics Genealogy Project Articles Published by early OSA Presidents Journal of the Optical Society of America
Emil Wolf
–
An example of a signature of Dr. Emil Wolf
13.
F. J. Duarte
–
Francisco Javier Frank Duarte is a Chilean-born laser physicist and author/editor of several well-known books on tunable lasers and quantum optics. He introduced the generalized multiple-prism dispersion theory, has discovered various multiple-prism grating oscillator laser configurations, duartes research has mainly focused on physical and laser optics and has taken place at a number of institutions in the academic, industrial, and defense sectors. Duarte and Piper introduced the multiple-prism near-grazing-incidence grating cavities originally disclosed as copper-laser-pumped narrow-linewidth tunable laser oscillators and he then introduced multiple-prism grating configurations to high-power CO2 laser oscillators. Duarte also developed the theories for narrow-linewidth dispersive laser oscillators, and multiple-prism laser pulse compression, the tunable narrow-linewidth laser oscillator configurations, introduced by Duarte and Piper, were adopted by various research groups working on uranium atomic vapor laser isotope separation. This work was supported by the Australian Atomic Energy Commission, during the course of this research, Duarte writes that he did approach the then federal minister for energy, Sir John Carrick, to advocate for the introduction of an AVLIS facility in Australia. In 2002, he participated in research that led to the separation of lithium using narrow-linewidth tunable diode lasers. From the mid-1980s to early 1990s Duarte and scientists from the US Army Missile Command developed ruggedized narrow-linewidth laser oscillators tunable directly in the visible spectrum and this constituted the first disclosure, in the open literature, of a tunable narrow-linewidth laser tested on a rugged terrain. This research led to experimentation with polymer gain media and in 1994 Duarte reported on the first narrow-linewidth tunable solid state dye laser oscillators and these dispersive oscillator architectures were then refined to yield single-longitudinal-mode emission limited only by Heisenbergs uncertainty principle. In 2005, Duarte and colleagues were the first to demonstrate directional coherent emission from an electrically excited organic semiconductor and these experiments utilized a tandem OLED within an interferometric configuration. In the late 1980s, Duarte invented the N-slit laser interferometer and applied Dirac’s notation to describe quantum mechanically its interferometric, Duarte also derived the cavity linewidth equation, for dispersive laser oscillators, using quantum mechanical principles. More recently, Duarte and colleagues have developed very large N-slit laser interferometers to generate and propagate interferometric characters for secure free-space optical communications, interferometric characters is a term coined in 2002 to link interefometric signals to alphanumerical characters. Duarte provides a description of quantum optics, almost entirely via Diracs notation, in this book he derives the probability amplitude for quantum entanglement, | ψ ⟩ =12 which he calls the Pryce-Ward probability amplitude, from an N-slit interferometric perspective. Duarte also emphasizes a pragmatic approach to quantum mechanics. At Macquarie University, Duarte studied quantum physics under John Clive Ward and his PhD research was on laser physics and his supervisor was James A. Piper. In the area of university politics, he established and led the successful Macquarie science reform movement, macquaries science reform, was widely supported by local scientists including physicists R. E. Aitchison, R. E. B. Makinson, A. W. Pryor, and J. C. Ward, in 1980, Duarte was elected as one of the Macquarie representatives to the Australian Union of Students from where he was expelled, and then reinstated, for running over the tables. Following completion of his PhD work, Duarte did post doctoral research, with B. J. Orr at the University of New South Wales, in 1983, Duarte traveled to the United States to assume a physics professorship at the University of Alabama. In 1985 he joined the Imaging Research Laboratories, at the Eastman Kodak Company, while at Kodak he was chairman of Lasers 87 and subsequent conferences in this series
F. J. Duarte
–
F. J. Duarte at a meeting of the
Optical Society in 2006.
F. J. Duarte
–
Duarte and colleagues demonstrated the superposition of diffraction patterns over N -slit interferograms. This interferogram corresponds to the interferometric character b (N = 3 slits) and exhibits a diffraction pattern superimposed on the right outer wing (see text).
F. J. Duarte
–
Duarte's
polarization rotator
14.
Sir Isaac Newton
–
His book Philosophiæ Naturalis Principia Mathematica, first published in 1687, laid the foundations of classical mechanics. Newton also made contributions to optics, and he shares credit with Gottfried Wilhelm Leibniz for developing the infinitesimal calculus. Newtons Principia formulated the laws of motion and universal gravitation that dominated scientists view of the universe for the next three centuries. Newtons work on light was collected in his influential book Opticks. He also formulated a law of cooling, made the first theoretical calculation of the speed of sound. Newton was a fellow of Trinity College and the second Lucasian Professor of Mathematics at the University of Cambridge, politically and personally tied to the Whig party, Newton served two brief terms as Member of Parliament for the University of Cambridge, in 1689–90 and 1701–02. He was knighted by Queen Anne in 1705 and he spent the last three decades of his life in London, serving as Warden and Master of the Royal Mint and his father, also named Isaac Newton, had died three months before. Born prematurely, he was a child, his mother Hannah Ayscough reportedly said that he could have fit inside a quart mug. When Newton was three, his mother remarried and went to live with her new husband, the Reverend Barnabas Smith, leaving her son in the care of his maternal grandmother, Newtons mother had three children from her second marriage. From the age of twelve until he was seventeen, Newton was educated at The Kings School, Grantham which taught Latin and Greek. He was removed from school, and by October 1659, he was to be found at Woolsthorpe-by-Colsterworth, Henry Stokes, master at the Kings School, persuaded his mother to send him back to school so that he might complete his education. Motivated partly by a desire for revenge against a bully, he became the top-ranked student. In June 1661, he was admitted to Trinity College, Cambridge and he started as a subsizar—paying his way by performing valets duties—until he was awarded a scholarship in 1664, which guaranteed him four more years until he would get his M. A. He set down in his notebook a series of Quaestiones about mechanical philosophy as he found it, in 1665, he discovered the generalised binomial theorem and began to develop a mathematical theory that later became calculus. Soon after Newton had obtained his B. A. degree in August 1665, in April 1667, he returned to Cambridge and in October was elected as a fellow of Trinity. Fellows were required to become ordained priests, although this was not enforced in the restoration years, however, by 1675 the issue could not be avoided and by then his unconventional views stood in the way. Nevertheless, Newton managed to avoid it by means of a special permission from Charles II. A and he was elected a Fellow of the Royal Society in 1672. Newtons work has been said to distinctly advance every branch of mathematics then studied and his work on the subject usually referred to as fluxions or calculus, seen in a manuscript of October 1666, is now published among Newtons mathematical papers
Sir Isaac Newton
–
Portrait of Isaac Newton in 1689 (age 46) by
Godfrey Kneller
Sir Isaac Newton
–
Newton in a 1702 portrait by
Godfrey Kneller
Sir Isaac Newton
–
Isaac Newton (Bolton, Sarah K. Famous Men of Science. NY: Thomas Y. Crowell & Co., 1889)
Sir Isaac Newton
–
Replica of Newton's second
Reflecting telescope that he presented to the
Royal Society in 1672
15.
Crown glass (optics)
–
Crown glass is a type of optical glass used in lenses and other optical components. It has relatively low refractive index and low dispersion, crown glass is produced from alkali-lime silicates containing approximately 10% potassium oxide and is one of the earliest low dispersion glasses. As well as the specific material named crown glass, there are other optical glasses with similar properties that are also called crown glasses, generally, this is any glass with Abbe numbers in the range 50 to 85. For example, the borosilicate glass Schott BK7 is a common crown glass. Borosilicates contain about 10% boric oxide, have good optical and mechanical characteristics, other additives used in crown glasses include zinc oxide, phosphorus pentoxide, barium oxide, fluorite and lanthanum oxide. A concave lens of flint glass is commonly combined with a lens of crown glass to produce an achromatic doublet. The dispersions of the glasses partially compensate for other, producing reduced chromatic aberration compared to a singlet lens with the same focal length
Crown glass (optics)
–
An
achromatic doublet, which combines crown glass and
flint glass.
16.
BK7 glass
–
Crown glass is a type of optical glass used in lenses and other optical components. It has relatively low refractive index and low dispersion, crown glass is produced from alkali-lime silicates containing approximately 10% potassium oxide and is one of the earliest low dispersion glasses. As well as the specific material named crown glass, there are other optical glasses with similar properties that are also called crown glasses, generally, this is any glass with Abbe numbers in the range 50 to 85. For example, the borosilicate glass Schott BK7 is a common crown glass. Borosilicates contain about 10% boric oxide, have good optical and mechanical characteristics, other additives used in crown glasses include zinc oxide, phosphorus pentoxide, barium oxide, fluorite and lanthanum oxide. A concave lens of flint glass is commonly combined with a lens of crown glass to produce an achromatic doublet. The dispersions of the glasses partially compensate for other, producing reduced chromatic aberration compared to a singlet lens with the same focal length
BK7 glass
–
An
achromatic doublet, which combines crown glass and
flint glass.
17.
Flint glass
–
Flint glass is optical glass that has relatively high refractive index and low Abbe number. Flint glasses are arbitrarily defined as having an Abbe number of 50 to 55 or less, the currently known flint glasses have refractive indices ranging between 1.45 and 2.00. With respect to glass, the term flint derives from the flint nodules found in the deposits of southeast England that were used as a source of high purity silica by George Ravenscroft. 1662, to produce a lead glass that was the precursor to English lead crystal. Traditionally, flint glasses were lead glasses containing around 4–60% lead oxide, however, in many modern flint glasses, lead oxides are replaced with other metal oxides such as titanium dioxide and zirconium dioxide without significantly altering the optical properties of the glass. Crown glass Chromatic aberration Cup plate Kurkjian, Charles R. and Prindle, journal of the American Ceramic Society,81, 795-813
Flint glass
–
An
achromatic doublet, which combines
crown glass and flint glass.
18.
Fused quartz
–
Fused quartz or fused silica is glass consisting of silica in amorphous form. It differs from traditional glasses in containing no other ingredients, which are added to glass to lower the melt temperature. Fused silica, therefore, has high working and melting temperatures, the optical and thermal properties of fused quartz are superior to those of other types of glass due to its purity. For these reasons, it use in situations such as semiconductor fabrication. It has better ultraviolet transmission than most other glasses, and so is used to make lenses and its low coefficient of thermal expansion also makes it a useful material for precision mirror substrates. Fused quartz is produced by fusing high-purity silica sand, which consists of quartz crystals, quartz contains only silicon and oxygen, although commercial quartz glass often contains impurities. The most dominant impurities are aluminium and titanium, melting is effected at approximately 1650 °C using either an electrically heated furnace or a gas/oxygen-fuelled furnace. This results in a transparent glass with a purity and improved optical transmission in the deep ultraviolet. Fused quartz is normally transparent, the process of fusion results in a material that is translucent, the material can however appear opaque owing to the presence of small air bubbles trapped within the material. The water content is determined by the manufacturing process, flame fused material always has a higher water content due to the combination of the hydrocarbons and oxygen fuelling the furnace forming hydroxyl groups within the material. An IR grade material typically has an content of <10 parts per million, most of the applications of fused silica exploit its wide transparency range, which extends from the UV to the near IR. Fused silica is the key starting material for optical fiber, used for telecommunications, vacuum tubes with silica envelopes allowed for radiation cooling by incandescent anodes. Because of its strength fused silica was used in deep diving vessels such as the Bathysphere, the combination of strength, thermal stability, and UV transparency makes it an excellent substrate for projection masks for photolithography. EPROMs are recognizable by the transparent fused quartz window which sits on top of the package, through which the chip is visible. Due to the stability and composition it is used in semiconductor fabrication furnaces. Fused quartz has nearly ideal properties for fabricating first surface mirrors such as used in telescopes. The material behaves in a way and allows the optical fabricator to put a very smooth polish onto the surface and produce the desired figure with fewer testing iterations. These lenses are used for UV photography, as the glass has a lower extinction rate than lens made with more common flint or crown glass formulas
Fused quartz
–
A fused quartz sphere manufactured for use in a gyroscope in the
Gravity Probe B experiment. It is one of the most accurate spheres ever manufactured, deviating from a perfect sphere by no more than 40 atoms of thickness. It is thought that only
neutron stars are smoother.
Fused quartz
–
An
EPROM with fused quartz window in the top of the package
Fused quartz
–
Phosphorescence in fused quartz from an extremely intense pulse of ultraviolet light, centered at 170 nm, in a flashtube.
Fused quartz
–
Phosphorescence of the quartz ignition tube of an
air-gap flash.
19.
Reflection (physics)
–
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves, the law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. In acoustics, reflection causes echoes and is used in sonar, in geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water, Reflection is observed with many types of electromagnetic wave, besides visible light. Reflection of VHF and higher frequencies is important for radio transmission, even hard X-rays and gamma rays can be reflected at shallow angles with special grazing mirrors. Reflection of light is either specular or diffuse depending on the nature of the interface, a mirror provides the most common model for specular light reflection, and typically consists of a glass sheet with a metallic coating where the reflection actually occurs. Reflection is enhanced in metals by suppression of wave propagation beyond their skin depths, Reflection also occurs at the surface of transparent media, such as water or glass. In the diagram, a light ray PO strikes a vertical mirror at point O, by projecting an imaginary line through point O perpendicular to the mirror, known as the normal, we can measure the angle of incidence, θi and the angle of reflection, θr. The law of reflection states that θi = θr, or in other words, in fact, reflection of light may occur whenever light travels from a medium of a given refractive index into a medium with a different refractive index. In the most general case, a fraction of the light is reflected from the interface. This is analogous to the way impedance mismatch in a circuit causes reflection of signals. Total internal reflection of light from a denser medium occurs if the angle of incidence is above the critical angle, total internal reflection is used as a means of focusing waves that cannot effectively be reflected by common means. X-ray telescopes are constructed by creating a tunnel for the waves. As the waves interact at low angle with the surface of this tunnel they are reflected toward the focus point, a conventional reflector would be useless as the X-rays would simply pass through the intended reflector. When light reflects off a material denser than the external medium, in contrast, a less dense, lower refractive index material will reflect light in phase. This is an important principle in the field of thin-film optics, specular reflection at a curved surface forms an image which may be magnified or demagnified, curved mirrors have optical power. Such mirrors may have surfaces that are spherical or parabolic, if the reflecting surface is very smooth, the reflection of light that occurs is called specular or regular reflection. The laws of reflection are as follows, The incident ray, the reflected ray, the angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal
Reflection (physics)
–
The reflection of
Mount Hood in
Mirror Lake.
Reflection (physics)
–
Double reflection: The sun is reflected in the water, which is reflected in the paddle.
Reflection (physics)
–
An example of the law of reflection
Reflection (physics)
–
Sound diffusion panel for high frequencies
20.
Prism compressor
–
A prism compressor is an optical device used to shorten the duration of a positively chirped ultrashort laser pulse by giving different wavelength components a different time delay. It typically consists of two prisms and a mirror, Figure 1 shows the construction of such a compressor. If the different wavelength components of a laser pulse were already separated in time, prism compressors are typically used to compensate for dispersion inside Ti, sapphire modelocked laser. Each time the laser pulse inside travels through the components inside the laser cavity. A prism compressor inside the cavity can be designed such that it exactly compensates this intra-cavity dispersion and it can also be used to compensate for dispersion of ultrashort pulses outside laser cavities. Prismatic pulse compression was first introduced, using a prism, in 1983 by Dietel et al. Additional experimental developments include a pulse compressor and a six-prism pulse compressor for semiconductor lasers. An additional compressor, using a prism with lateral reflectors to enable a multi-pass arrangement at the prism, was introduced in 2006. Almost all optical materials that are transparent for light have a normal, or positive, dispersion. This means that longer wavelengths travel faster through these materials, the same is true for the prisms in a prism compressor. However, the dispersion of the prisms is offset by the extra distance that the longer wavelength components have to travel through the second prism. This is a delicate balance, since the shorter wavelengths travel a larger distance through air. However, with a choice of the geometry, it is possible to create a negative dispersion that can compensate positive dispersion from other optical components. This is shown in Figure 3, by shifting prism P2 up and down, the dispersion of the compressor can be both negative around refractive index n =1.6 and positive. The range with a dispersion is relatively short since prism P2 can only be moved upwards over a short distance before the light ray misses it altogether. In principle, the α angle can be varied to tune the properties of a prism compressor. In practice, however, the geometry is chosen such that the incident and this configuration is known as the angle of minimum deviation, and is easier to align than arbitrary angles. The refractive index of materials such as BK7 glass changes only a small amount within the few tens of nanometers that are covered by an ultrashort pulse
Prism compressor
–
Figure 1. A prism compressor. The red lines represent
rays of longer wavelengths and the blue lines those of shorter wavelengths. The spacing of the red, green, and blue wavelength components after the compressor is drawn to scale. This setup has a positive dispersion.
21.
Ultrafast
–
In optics, an ultrashort pulse of light is an electromagnetic pulse whose time duration is of the order of a picosecond or less. Such pulses have an optical spectrum, and can be created by mode-locked oscillators. They are commonly referred to as ultrafast events, amplification of ultrashort pulses almost always requires the technique of chirped pulse amplification, in order to avoid damage to the gain medium of the amplifier. They are characterized by a peak intensity that usually leads to nonlinear interactions in various materials. These processes are studied in the field of nonlinear optics, in the specialized literature, ultrashort refers to the femtosecond and picosecond range, although such pulses no longer hold the record for the shortest pulses artificially generated. Indeed, x-ray pulses with durations on the time scale have been reported. The 1999 Nobel Prize in Chemistry was awarded to Ahmed H. Zewail for using ultrashort pulses to observe chemical reactions on the timescales they occur on, there is no standard definition of ultrashort pulse. A common example is a chirped Gaussian pulse, a wave whose field amplitude follows a Gaussian envelope, the real electric field corresponding to an ultrashort pulse is oscillating at an angular frequency ω0 corresponding to the central wavelength of the pulse. To facilitate calculations, a complex field E is defined, formally, it is defined as the analytic signal corresponding to the real field. Such a chirp may be acquired as a pulse propagates through materials and is due to their dispersion and it results in a temporal broadening of the pulse. The intensity functions—temporal I and spectral S—determine the time duration and spectrum bandwidth of the pulse, as stated by the uncertainty principle, their product has a lower bound. This minimum value depends on the used for the duration and on the shape of the pulse. For a given spectrum, the minimum time-bandwidth product, and therefore the shortest pulse, is obtained by a transform-limited pulse, high values of the time-bandwidth product, on the other hand, indicate a more complex pulse. One of them is the compressor, a device that can be used to control the spectral phase of ultrashort pulses. It is composed of a sequence of prisms, or gratings, when properly adjusted it can alter the spectral phase φ of the input pulse so that the output pulse is a bandwidth-limited pulse with the shortest possible duration. A pulse shaper can be used to more complicated alterations on both the phase and the amplitude of ultrashort pulses. To accurately control the pulse, a full characterization of the spectral phase is a must in order to get certain pulse spectral phase. Then, a spatial light modulator can be used in the 4f plane to control the pulse, Multiphoton intrapulse interference phase scan is a technique based on this concept
Ultrafast
–
A positively chirped ultrashort pulse of light in the time domain.
22.
Abbe prism
–
In optics, an Abbe prism, named for its inventor, the German physicist Ernst Abbe, is a type of constant deviation dispersive prism similar to a Pellin–Broca prism. The prism consists of a block of glass forming a right prism with 30°–60°–90° triangular faces, when in use, a beam of light enters face AB, is refracted and undergoes total internal reflection from face BC, and is refracted again on exiting face AC. The prism is designed such that one wavelength of the light exits the prism at a deviation angle of exactly 60°. This is the minimum possible deviation of the prism, all other wavelengths being deviated by greater angles, by rotating the prism around any point O on the face AB, the wavelength which is deviated by 60° can be selected. The dispersive Abbe prism should not be confused with the non-dispersive Porro–Abbe or Abbe–Koenig prisms
Abbe prism
–
Abbe prism (serving suggestion only, image not accurate)
23.
Amici prism
–
An Amici prism, named for the astronomer Giovanni Amici, is a type of compound dispersive prism used in spectrometers. The Amici prism consists of two triangular prisms in contact, with the first typically being made from a crown glass. Light entering the first prism is refracted at the first air-glass interface, the prism angles and materials are chosen such that one wavelength of light, the centre wavelength, exits the prism parallel to the entrance beam. The prism assembly is thus a direct-vision prism, and is used as such in hand-held spectroscopes. Other wavelengths are deflected at angles depending on the dispersion of the materials. Looking at a light source through the prism thus shows the spectrum of the source. By 1860, Amici realized that one can join this type of prism back-to-back with a copy of itself. The exiting ray of the wavelength is thus not only undeviated from the incident ray. Amici himself never published about his nondeviating prism, but rather communicated the idea to his friend Donati, however, the dispersion of Amici prisms can be accurately calculated using the multiple-prism dispersion theory assuming no spatial separation between the prism components. The dispersive Amici prism should not be confused with the non-dispersive Amici roof prism
Amici prism
–
An Amici Prism
Amici prism
–
Prism segmentation of a double Amici prism
Amici prism
–
A
compact fluorescent lamp seen through an Amici prism
24.
Compound prism
–
A compound prism is a set of multiple triangular prism elements placed in contact, and often cemented together to form a solid assembly. The use of elements gives several advantages to an optical designer. Thus, light at the wavelength which enters at an angle θ0 with respect to the optical axis. This kind of effect is called direct vision dispersion or nondeviating dispersion. One can achieve deviation of the incident beam while also reducing the dispersion introduced into the beam. This effect is used in beam steering, One can tune the prism dispersion to achieve greater dispersion linearity or to achieve higher-order dispersion effects. The simplest compound prism is a doublet, consisting of two elements in contact, as shown in the figure at right. A ray of light passing through the prism is refracted at the first air-glass interface, the deviation angle δ of the ray is given by the difference in ray angle between the incident ray and the exiting ray, δ = θ0 − θ4. While one can produce direct vision dispersion from doublet prisms, there is typically significant displacement of the beam, note that α i indicates that the prism is inverted. The central wavelength of the spectrum is denoted λ ¯, doublet prisms are often used for direct-vision dispersion. Note that this formula is accurate under the small angle approximation. While the doublet prism is the simplest compound prism type, the prism is much more common. This prism is a three-element system, in which the first, the design layout is thus symmetric about the plane passing through the center of its second element. Thus, we can derive the expressions for the angles using these linear equations. The double-Amici prism is a form of the more general triplet prism. Although triplet prisms are rarely found in systems, their added degrees of freedom beyond the double-Amici design allow for improved dispersion linearity
Compound prism
–
One can achieve
spectral dispersion without causing the deviation of the beam at the design wavelength. Thus, light at the design wavelength which enters at an angle with respect to the optical axis, exits the prism at the same angle with respect to the same axis. This kind of effect is often called "direct vision dispersion" or "nondeviating dispersion".
25.
Diffraction grating
–
In optics, a diffraction grating is an optical component with a periodic structure, which splits and diffracts light into several beams travelling in different directions. The emerging coloration is a form of structural coloration, the directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as the dispersive element. Because of this, gratings are used in monochromators and spectrometers. For practical applications, gratings generally have ridges or rulings on their surface rather than dark lines, such gratings can be either transmissive or reflective. Gratings which modulate the phase rather than the amplitude of the incident light are also produced, the principles of diffraction gratings were discovered by James Gregory, about a year after Newtons prism experiments, initially with items such as bird feathers. The first man-made diffraction grating was made around 1785 by Philadelphia inventor David Rittenhouse and this was similar to notable German physicist Joseph von Fraunhofers wire diffraction grating in 1821. Diffraction can create rainbow colors when illuminated by a wide spectrum light source, a grating has parallel lines, while a CD has a spiral of finely-spaced data tracks. Diffraction colors also appear when one looks at a point source through a translucent fine-pitch umbrella-fabric covering. Decorative patterned plastic films based on reflective grating patches are very inexpensive, the relationship between the grating spacing and the angles of the incident and diffracted beams of light is known as the grating equation. Gratings may be of the reflective or transmissive type, analogous to a mirror or lens, respectively. A grating has a mode, in which there is no diffraction. An idealised grating is considered here which is made up of a set of slits of spacing d, assuming a plane wave of monochromatic light of wavelength λ with normal incidence, each slit in the grating acts as a quasi point-source from which light propagates in all directions. After light interacts with the grating, the light is composed of the sum of interfering wave components emanating from each slit in the grating. At any given point in space through which diffracted light may pass, similarly, when the path difference is λ, the phases will add together and maxima will occur. Thus, when light is incident on the grating, the diffracted light will have maxima at angles θm given by. It is straightforward to show if a plane wave is incident at any arbitrary angle θi. When solved for the diffracted angle maxima, the equation is, please note that these equations assume that both sides of the grating are in contact with the same medium. The light that corresponds to direct transmission is called the zero order, the other maxima occur at angles which are represented by non-zero integers m
Diffraction grating
–
A very large reflecting diffraction grating
Diffraction grating
–
An incandescent light-bulb viewed through a transmissive diffraction grating. [
dubious –
discuss]
Diffraction grating
–
A diffraction grating reflecting only the green portion of the spectrum from a room's fluorescent lighting
Diffraction grating
–
A helical fluorescent lamp photographed in a reflection diffraction-grating, showing the various spectral lines produced by the lamp.
26.
Optical telescope
–
The larger the objective, the more light the telescope collects and the finer detail it resolves. People use telescopes and binoculars for activities such as astronomy, ornithology, pilotage and reconnaissance. The telescope is more a discovery of optical craftsmen than an invention of a scientist and it is in the Netherlands in 1608 where the first recorded optical telescopes appeared. The invention is credited to the spectacle makers Hans Lippershey and Zacharias Janssen in Middelburg, galileo greatly improved on these designs the following year, and is generally credited as the first to use a telescope for astronomy. Galileos telescope used Hans Lippersheys design of an objective lens and a concave eye lens. Johannes Kepler proposed an improvement on the design used a convex eyepiece. For reflecting telescopes, which use a mirror in place of the objective lens. The theoretical basis for curved mirrors behaving similar to lenses was probably established by Alhazen, the late 20th century has seen the development of adaptive optics and space telescopes to overcome the problems of astronomical seeing. The basic scheme is that the primary light-gathering element the objective and this image may be recorded or viewed through an eyepiece, which acts like a magnifying glass. The eye then sees an inverted magnified virtual image of the object, most telescope designs produce an inverted image at the focal plane, these are referred to as inverting telescopes. In fact, the image is both turned upside down and reversed left to right, so that altogether it is rotated by 180 degrees from the object orientation, in astronomical telescopes the rotated view is normally not corrected, since it does not affect how the telescope is used. However, a diagonal is often used to place the eyepiece in a more convenient viewing location, and in that case the image is erect. In terrestrial telescopes such as spotting scopes, monoculars and binoculars, There are telescope designs that do not present an inverted image such as the Galilean refractor and the Gregorian reflector. These are referred to as erecting telescopes, many types of telescope fold or divert the optical path with secondary or tertiary mirrors. These may be part of the optical design, or may simply be used to place the eyepiece or detector at a more convenient position. Telescope designs may also use specially designed additional lenses or mirrors to improve image quality over a field of view. Design specifications relate to the characteristics of the telescope and how it performs optically, several properties of the specifications may change with the equipment or accessories used with the telescope, such as Barlow lenses, star diagonals and eyepieces. These interchangeable accessories dont alter the specifications of the telescope, however they alter the way the telescopes properties function, typically magnification, angular resolution and FOV
Optical telescope
–
Eight-inch refracting telescope at
Chabot Space and Science Center
Optical telescope
–
Two of the four Unit Telescopes that make up the
ESO 's
VLT, on a remote mountaintop, 2600 metres above sea level in the Chilean Atacama Desert.
Optical telescope
–
Harlan J. Smith Telescope reflecting telescope at
McDonald Observatory, Texas
27.
Stellar spectrum
–
Astronomical spectroscopy is used to measure three major bands of radiation, visible spectrum, radio, and X-ray. While all spectroscopy looks at areas of the spectrum, different methods are required to acquire the signal depending on the frequency. Ozone and molecular oxygen absorb light with wavelengths under 300 nm, meaning that X-ray, radio signals have much longer wavelengths than optical signals, and require the use of antennas or radio dishes. Physicists have been looking at the solar spectrum since Isaac Newton first used a prism to observe the refractive properties of light. In the early 1800s Joseph von Fraunhofer used his skills as a maker to create very pure prisms. The resolution of a prism is limited by its size, a prism will provide a more detailed spectrum. This issue was resolved in the early 1900s with the development of high-quality reflection gratings by J. S, plaskett at the Dominion Observatory in Ottawa, Canada. By creating a blazed grating which utilizes a number of parallel mirrors. These new spectroscopes were more detailed than a prism, required less light, the limitation to a blazed grating is the width of the mirrors, which can only be ground a finite amount before focus is lost, the maximum is around 1000 lines/mm. In order to overcome this limitation holographic gratings were developed, volume phase holographic gratings use a thin film of dichromated gelatin on a glass surface, which is subsequently exposed to a wave pattern created by an interferometer. The holographic gratings can have up to 6000 lines/mm and can be up to twice as efficient in collecting light as blazed gratings, because they are sealed between two sheets of glass, the holographic gratings are very versatile, potentially lasting decades before needing replacement. Light dispersed by the grating or prism in a spectrograph can be recorded by a detector, historically, photographic plates were widely used to record spectra until electronic detectors were developed, and today optical spectrographs most often employ charge-coupled devices. The wavelength scale of a spectrum can be calibrated by observing the spectrum of emission lines of known wavelength from a gas-discharge lamp, radio astronomy was founded with the work of Karl Jansky in the early 1930s, while working for Bell Labs. He built an antenna to look at potential sources of interference for transatlantic radio transmissions. One of the sources of noise discovered came not from Earth, in 1942, JS Hey captured the suns radio frequency using military radar receivers. Radio spectroscopy started with the discovery of the 21-centimeter H I line in 1951, radio interferometry was pioneered in 1946, when Joseph Lade Pawsey, Ruby Payne-Scott and Lindsay McCready used a single antenna atop a sea cliff to observe 200 MHz solar radiation. Two incident beams, one directly from the sun and the other reflected from the sea surface, the first multi-receiver interferometer was built in the same year by Martin Ryle and Vonberg. In 1960, Ryle and Antony Hewish published the technique of aperture synthesis to analyze interferometer data, the aperture synthesis process, which involves autocorrelating and discrete Fourier transforming the incoming signal, recovers both the spatial and frequency variation in flux
Stellar spectrum
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The Star-Spectroscope of the Lick Observatory in 1898
Stellar spectrum
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Incident light reflects at the same angle (black lines), but a small portion of the light is refracted as coloured light (red and blue lines).
28.
Pink Floyd
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Pink Floyd were an English rock band formed in London. They achieved international acclaim with their progressive and psychedelic music, Pink Floyd were founded in 1965 by students Syd Barrett on guitar and lead vocals, Nick Mason on drums, Roger Waters on bass and vocals, and Richard Wright on keyboards and vocals. Guitarist David Gilmour joined in December 1967, Barrett left in April 1968 due to deteriorating mental health. Waters became the primary lyricist and conceptual leader, devising the concepts behind their albums The Dark Side of the Moon, Wish You Were Here, Animals, The Wall. The Dark Side of the Moon and The Wall became two of the albums of all time. Following creative tensions, Wright left Pink Floyd in 1979, followed by Waters in 1985, Gilmour and Mason continued as Pink Floyd, Wright rejoined them as a session musician and, later, a band member. The three produced two more albums—A Momentary Lapse of Reason and The Division Bell —and toured through 1994, Barrett died in 2006, and Wright in 2008. The final Pink Floyd studio album, The Endless River, was recorded without Waters, Pink Floyd were inducted into the American Rock and Roll Hall of Fame in 1996 and the UK Music Hall of Fame in 2005. By 2013, the band had more than 250 million records worldwide. Roger Waters met Nick Mason while they were both studying architecture at the London Polytechnic at Regent Street and they first played music together in a group formed by Keith Noble and Clive Metcalfe with Nobles sister Sheilagh. Richard Wright, an architecture student, joined later that year. Waters played lead guitar, Mason drums, and Wright rhythm guitar, the band performed at private functions and rehearsed in a tearoom in the basement of the Regent Street Polytechnic. They performed songs by the Searchers and material written by their manager and songwriter, Mason moved out after the 1964 academic year, and guitarist Bob Klose moved in during September 1964, prompting Waters switch to bass. Sigma 6 went through several names, including the Meggadeaths, the Abdabs and the Screaming Abdabs, Leonards Lodgers, in 1964, as Metcalfe and Noble left to form their own band, guitarist Syd Barrett joined Klose and Waters at Stanhope Gardens. Barrett, two younger, had moved to London in 1962 to study at the Camberwell College of Arts. Waters and Barrett were childhood friends, Waters had often visited Barrett, Noble and Metcalfe left the Tea Set in late 1963, and Klose introduced the band to singer Chris Dennis, a technician with the Royal Air Force. In December 1964, they secured their first recording time, at a studio in West Hampstead, through one of Wrights friends, Wright, who was taking a break from his studies, did not participate in the session. When the RAF assigned Dennis a post in Bahrain in early 1965, later that year, they became the resident band at the Countdown Club near Kensington High Street in London, where from late night until early morning they played three sets of 90 minutes each
Pink Floyd
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Pink Floyd in January 1968, from the only known photo-shoot of all five members. Clockwise from bottom: Gilmour, Mason, Barrett, Waters, Wright
Pink Floyd
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The psychedelic artwork for
A Saucerful of Secrets was the first of many Pink Floyd covers designed by
Hipgnosis
Pink Floyd
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Waters performing with Pink Floyd at
Leeds University in 1970
Pink Floyd
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Pink Floyd in 1973
29.
The Dark Side of the Moon
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The Dark Side of the Moon is the eighth album by English rock band Pink Floyd, released on 1 March 1973 by Harvest Records. It thematically explores conflict, greed, the passage of time, and mental illness, developed during live performances, an early version was premiered several months before recording began, new material was recorded in two sessions in 1972 and 1973 at Abbey Road in London. The group used some advanced recording techniques at the time, including multitrack recording, analogue synthesizers were prominent in several tracks, and snippets from recorded interviews with Pink Floyds road crew and others provided philosophical quotations throughout. Engineer Alan Parsons was responsible for many distinctively notable sonic aspects, the album was an immediate commercial and critical success, it topped the Billboard Top LPs & Tapes chart for a week and remained in the chart for 741 weeks from 1973 to 1988. With an estimated 45 million copies sold, it is Pink Floyds most commercially successful album and it has been remastered and re-released twice, and covered in its entirety by several other acts. It produced two singles, Money and Us and Them, and is the bands most popular album among fans and critics, following Meddle in 1971, Pink Floyd assembled for an upcoming tour of Britain, Japan and the United States in December of that year. Rehearsing in Broadhurst Gardens in London, there was the prospect of a new album. In a band meeting at drummer Nick Masons home in Camden, the band had explored a similar idea with 1969s The Man and The Journey. In an interview for Rolling Stone, guitarist David Gilmour said, I think we all thought –, There was definitely a feeling that the words were going to be very clear and specific. Generally, all four members agreed that Waters album concept unified by a theme was a good idea. The band rehearsed at a warehouse in London owned by The Rolling Stones and they also purchased extra equipment, which included new speakers, a PA system, a 28-track mixing desk with four quadraphonic outputs, and a custom-built lighting rig. However, after discovering that that title had already used by another band, Medicine Head. The new material premièred at The Dome in Brighton, on 20 January 1972, michael Wale of The Times described the piece as. It was so understanding and musically questioning. Derek Jewell of The Sunday Times wrote The ambition of the Floyds artistic intention is now vast. Melody Maker was, however, less enthusiastic, Musically, there were great ideas. However, the tour was praised by the public. The bands lengthy tour through Europe and North America gave them the opportunity to make improvements to the scale
The Dark Side of the Moon
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The Dark Side of the Moon
The Dark Side of the Moon
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Album art by
Hipgnosis and
George Hardie
The Dark Side of the Moon
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The
Rainbow Theatre in London, where The Dark Side of the Moon was played for the press in 1972
The Dark Side of the Moon
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Abbey Road Studios
30.
Multiple-prism dispersion theory
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The first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813, a modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959. The generalized multiple-prism dispersion theory was introduced by Duarte and Piper in 1982, similarly, ϕ2, m is the exit angle and ψ2, m its corresponding angle of refraction. The two main equations give the first order dispersion for an array of m prisms at the surface of the mth prism. The plus sign in the term in parentheses refers to a positive dispersive configuration while the minus sign refers to a compensating configuration. The k factors are the corresponding beam expansions, and the H factors are additional geometrical quantities and it can also be seen that the dispersion of the mth prism depends on the dispersion of the previous prism. A comprehensive review on practical multiple-prism beam expanders and multiple-prism angular dispersion theory, including explicit, more recently, the generalized multiple-prism dispersion theory has been extended to include positive and negative refraction. Also, higher order phase derivatives have been derived using a Newtonian iterative approach and this extension of the theory enables the evaluation of the Nth higher derivative via an elegant mathematical framework. Applications include further refinements in the design of prism pulse compressors, although originally classical in origin, in 1992 it was shown that this laser cavity linewidth equation can also be derived from interferometric quantum principles. In practice, M can be as high as 100-200, in 1987 the multiple-prism angular dispersion theory was extended to provide explicit second order equations directly applicable to the design of prismatic pulse compressors. Beam expander Laser linewidth Multiple-prism grating laser oscillator Prism and Multiple-Prism Pulse Compression, Tutorial
Multiple-prism dispersion theory
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Multiple-prism beam expander grating configuration as used in narrow-linewidth tunable laser oscillators
Multiple-prism dispersion theory
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A two-prism pulse compressor as deployed in some femtosecond laser configurations.
Multiple-prism dispersion theory
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This multiple-prism arrangement is used with a
diffraction grating to provide tuning in a dye laser.
31.
Light
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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to light, which is visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m. This wavelength means a range of roughly 430–750 terahertz. The main source of light on Earth is the Sun, sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the used by living things. Historically, another important source of light for humans has been fire, with the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence, for example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey. Visible light, as all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term sometimes refers to electromagnetic radiation of any wavelength. In this sense, gamma rays, X-rays, microwaves and radio waves are also light, like all types of light, visible light is emitted and absorbed in tiny packets called photons and exhibits properties of both waves and particles. This property is referred to as the wave–particle duality, the study of light, known as optics, is an important research area in modern physics. Generally, EM radiation, or EMR, is classified by wavelength into radio, microwave, infrared, the behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths, when EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries. There exist animals that are sensitive to various types of infrared, infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it, above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the eye cannot detect the very short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, various sources define visible light as narrowly as 420 to 680 to as broadly as 380 to 800 nm
Light
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An example of refraction of light. The straw appears bent, because of refraction of light as it enters liquid from air.
Light
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A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) get separated.
Light
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A
cloud illuminated by
sunlight
Light
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A
city illuminated by
artificial lighting
