Y. Dadoenkova, N. Dadoenkova, M. Krawczyk, and I. Lyubchanskii     
Opt. Lett. 43, 3965 (2018)

The lateral shift of an optical beam undergoing Brillouin light scattering on an acoustic wave (AW) in the total internal reflection geometry is studied theoretically. It is shown that the lateral shift depends on polarization (longitudinal or transversal) of the AW, as well as on the type of scattering process: a direct one, when the scattered wave undergoes a lateral shift at reflection from the interface, or a cascading one, when a fundamental frequency light beam is laterally shifted at reflection and then scattered on the AW.

Fig.1. Schematics of the direct (a) and cascade (b) BLS processes. Here s and p denote s- and p-polarized light, ω and Ω are the fundamental light frequency and frequency of the AW, and ΔS is the GH shift.