Louis Marcel Brillouin (1854-1948) was a French physicist and mathematician. Brillouin scattering, proposed by Brillouin in 1922, is a phenomenon used to study acoustic vibrations in gases, liquids, and solids. The essence of Brillouin scattering is the non-elastic scattering of light due to its interaction with acoustic phonons. It can be divided into spontaneous Brillouin scattering and stimulated Brillouin scattering.