The mechanism of stimulated Raman scattering of light in silicon doped with helium-like donors

Silicon doped with neutral helium-like magnesium donors was theoretically studied as an active medium in the terahertz frequency range. The inversion mechanism implemented in Si: Mg does not have the necessary efficiency under optical excitation due to the presence of fast relaxation processes. On the contrary, the mechanism of stimulated Raman scattering is less sensitive to relaxation times and allows one to obtain rearrangement of the generation spectrum. The important feature of doubly charged donors is the presence of two Stokes shifts in the system, which makes it possible to significantly expand the range of emitted frequencies. Calculations show that the combined use of uniaxial deformation of the crystal and the restructuring of the excitation quantum energy in the range of 95 – 105 meV (23 – 25.5 THz) will make it possible to obtain SRS in the frequency band of 7 – 33 meV (∼1.5 – 8 THz).