Stimulated Raman scattering in lithium formate monohydrate crystals at temperatures from 2 to 300 K

Abstract
Stimulated Raman scattering in x-, y-, and z-cut lithium formate monohydrate (LiHCOO⋅H2O) crystals was studied in a resonator configuration with use of a Q-switched ruby laser. The temperature dependence of the stimulated Raman threshold intensity was measured from 2 to 300 K for different polarizations of the laser light. Stimulated Raman scattering from the 79-cm1 yy A1(z) mode, the 104- or 1372-cm1 zz A1(z) modes, the 76-cm1 A2 mode, or the 82-, 113-, or 163-cm1 B1(x) modes was observed, depending on the propagation direction in the crystal, the polarization of the laser light, and the temperature. The results of stimulated Raman scattering are discussed using the measured temperature-dependent spontaneous Raman data from the same lattice modes. Steady-state and transient theories of stimulated Raman scattering for a broadband pump laser (ruby-laser linewidth 0.7 cm1) are applied to explain the experimental results.