Competition between stimulated Brillouin scattering and two-photon absorption in dispersed boron nitride

The design of transparent optical materials with stimulated Brillouin scattering (SBS) suppression is a topic of current interest. We measured two-photon absorption (2PA) cross-section sigma(2PA) and Brillouin gain factor g(B) of a suspension of hexagonal boron nitride (hBN) in N-methyl-2-pyrrolidone at the second harmonic of a Nd:YAG laser. SBS exhibits a significant quenching with hBN concentration, like previously observed in graphene suspension. The melting of hBN flakes due to a large 2PA and the related changes in the acoustic damping coefficient explain the quenching mechanism. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement