Inelastic collision of terahertz.acoustic phonons in ruby crystals
Basun S. A., Kaplyanskii A. A., Feofilov S. P.
An inelastic interaction of a focused beam of 0.87-THz transverse ballistic phonons with higher frequency (ω> 2 THz) phonons has been observed in a ruby at Τ = 1.8 К by means of a technique for the optical detection of nonequilibrium acoustic phonons.