Brillouin Scattering: A Tool for the Measurement of Elastic and Photoelastic Constants

After an outline of the Brillouin effect and of elastic waves in crystals, a method for the determination of elastic and photoelastic constants is analyzed. The authors propose a set of conditions with a view to obtaining accurately the numerical values of elastic and photoelastic constants and to ascertain their sign. The Brillouin-line intensities for scattering angles of 90^∘{} and 180^∘{} are presented for all crystal systems, except for the monoclinic and triclinic ones, and for the low-symmetry classes of the rhombohedric system.