  We studied helicity resolved Raman scattering in PtSe$_2$ flakes with
different thicknesses. The peak amplitude of helicity-switched Raman scattering
is significantly larger than that of helicity-conserved scattering for the
in-plane $E_{g}$ mode, consistent with the Raman tensor analyses and
conservation law of angular momentum. The peak amplitude of the
helicity-switched $E_{g}$ mode is larger for the thinner flakes. In addition,
we find Raman peaks near the energy levels of infrared (IR)-active $E_u$ and
$A_{2u}$ modes, only for monolayer and a few-layers thick flakes.
Interestingly, these peaks manifest themselves only for helicity-switched Raman
scattering; they are nearly absent for helicity-conserved scattering.
