text: Raman had association with the Banaras Hindu University in Varanasi. He attended the foundation ceremony of BHU and delivered lectures on mathematics and "Some new paths in physics" during the lecture series organised at the university from 5 to 8 February 1916. He also held the position of permanent visiting professor.
  With Suri Bhagavantam, he determined the spin of photons in 1932, which further confirmed the quantum nature of light. With another student, Nagendra Nath, he provided the correct theoretical explanation for the acousto-optic effect (light scattering by sound waves) in a series of articles resulting in the celebrated Raman–Nath theory. Modulators, and switching systems based on this effect have enabled optical communication components based on laser systems.
  Other investigations he carried out included experimental and theoretical studies on the diffraction of light by acoustic waves of ultrasonic and hypersonic frequencies, and those on the effects produced by X-rays on infrared vibrations in crystals exposed to ordinary light which were published between 1935 and 1942.
  In 1948, through studying the spectroscopic behaviour of crystals, he approached the fundamental problems of crystal dynamics in a new manner. He dealt with the structure and properties of diamond from 1944 to 1968, the structure and optical behaviour of numerous iridescent substances including labradorite, pearly feldspar, agate, quartz, opal, and pearl in the early 1950s. Among his other interests were the optics of colloids, and electrical and magnetic anisotropy. His last interests in the 1960s were on biological properties such as the colours of flowers and the physiology of human vision.