Sir Chandrasekhara Venkata Raman was an Indian physicist known for his work in the field of light scattering. Using a spectrograph that he developed, he and his student K. S. Krishnan discovered that when light traverses a transparent material, the deflected light changes its wavelength and frequency. This phenomenon, a hitherto unknown type of scattering of light, which they called "modified scattering" was subsequently termed the Raman effect or Raman scattering. Raman received the 1930 Nobel Prize in Physics for the discovery and was the first Asian to receive a Nobel Prize in any branch of science.
Raman in 1930
Raman at the 1930 Nobel Prize Award Ceremony with other winners, from left C. V. Raman (physics), Hans Fischer (chemistry), Karl Landsteiner (medicine) and Sinclair Lewis (literature)
Title page to Raman's Molecular Diffraction of Light (1922)
Bust of Chandrasekhara Venkata Raman in the garden of Birla Industrial & Technological Museum.
In physics, Raman scattering or the Raman effect is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrational energy being gained by a molecule as incident photons from a visible laser are shifted to lower energy. This is called normal Stokes-Raman scattering.
First page of Molecular Diffraction of Light (1922)