Stimulated Brillouin scattering in dispersed graphene

We explored the Stimulated Brillouin scattering (SBS) behavior of a transparent liquid containing a low concentration of strongly absorbing nanoparticles. We measured SBS energies in N-methyl-2-pyrrolidone (NMP) and water at 532 nm-wavelength. The previously unknown NMP Brillouin gain factor is g(B) = 18.6 +/- 1.8 cm.GW(-1). Graphene nanoflakes suspended in liquids strongly quench SBS. Lincar dependence of the SBS-threshold on the graphene absorption coefficient (concentration) makes it suitable for the detection of small nanoparticles quantities in water, with a minimal detectable concentration of 5.10(-8) g.cm(-3). The effect is interpreted as an antagonism between electrostriction and thermal expansion, which is induced by the formation of carbon vapor bubbles. It is very sensitive to changes in density, refractive index and acoustic absorption coefficient. which parameters can be determined in the SBS method. including access to the bubbling nanosecond dynamics. SBS suppression may find applications in laser technologies and optical telecommunication networks. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement