The phenomenon of coherent radiation attenuation in the cyclotron resonance of surface Dirac fermions in three-dimensional topological insulators was first discovered. I The angular dependences of the Raman scattering intensity of linearly and circularly polarized light on Si optical phonons are investigated. The measurements were carried out at T = 300 K in the geometry of backscattering from the (100), (111) and (110) Si planes. The spectra were excited by the Ar laser line with  = 488 nm. It is shown that for LO phonons the angular momentum is equal to zero, and for TO phonons it is 2ħ and 0 depending on the scattering geometry