Evanescent field Raman scattering of light is proposed as a method for
probing roton-type peculiarities of the excitation spectrum of 2D ele
ctron gas in a strong magnetic field. These peculiarities are essentia
l for the modern theories of the fractional quantum Hall effect. We pr
edict the magnetoroton contribution to bc comparable to the intensity,
measured in the conventional backscattering geometry. This method may
also be applied to 3D samples, exhibiting the roton-type spectrum of
quasiparticles. Particularly, in the familiar case of rotons in liquid
He-4, we show that the contribution of evanescent field Raman scatter
ing by rotons is expected to be comparable to the Mandelstam-Brillouin
contribution.