Resonant stimulated Raman scattering on the 2$^{3}S-1^{1}S$ forbidden transition of a helium atom

Resonant stimulated Raman scattering (SRS) from the 2$^{3}S-1^{1}S$ forbidden transition in a helium atom (62.6 nm) via the intermediate 2$^{3}P_{1}$ level has been considered. The metastable 2$^{3}S$ state has the lowest energy in the triplet spectral region (He$^*$), and the ground state is 1$^{1}S$. The reduced kinetic equations for the density matrix, which are used to analyze the SRS resonance, have been derived. The expressions for the field broadening and resonance shift are obtained, the Doppler broadening is taken into account, and numerical estimations are performed.