Blue laser
Videos
A blue laser emits electromagnetic radiation with a wavelength between 400 and 500 nanometers, which the human eye sees in the visible spectrum as blue or violet.
Trails of a 20 mW 405 nm violet laser shows clear fluorescence on some objects
445–450 nm blue laser (middle)
Quantum well
Videos
A quantum well is a potential well with only discrete energy values.
A heterostructure made from semiconductors AlGaAs (large band-gap) and GaAs (smaller band-gap) in a quantum well configuration. In the central GaAs region of length d, the conduction band energy is lower, and the valence band energy is higher. Therefore both electrons and holes can be confined in the GaAs region.
The first two energy states in an infinite well quantum well model. The walls in this model are assumed to be infinitely high. The solution wave functions are sinusoidal and go to zero at the boundary of the well.
A heterostructure made of AlAs and GaAs arranged in a superlattice configuration. In this case, the resulting periodic potential arises due to the difference in band-gaps between materials.
Image: MCM QW FINWELL