Terahertz Raman laser based on silicon doped by phosphorus

Raman-type stimulated emission at frequencies between 5.0 and 5.2 THz as well as between 6.1 and 6.4 THz has been realized in silicon crystals doped by phosphorus donors. The Raman laser operates at around 5 K under optical excitation by a pulsed, frequency-tunable infrared free electron laser. The Stokes shift of 3.16 THz is equal to the difference between the energies of the phosphorus ground state, 1s(A
₁
), and the 1s(E) split off state.