Spontaneous and Stimulated Raman Scattering in Sodium Dimolybdate Crystal

Abstract

Investigation of spontaneous and stimulated Raman scattering in a crystal of sodium dimolybdate, Na₂Mo₂O₇ with an orthorhombic structure is presented. Polarized Raman spectra corresponding to six independent components of the Raman tensor have been obtained. The phonon frequencies were determined and the oscillations were identified by types of symmetry. Raman-laser mode in Na₂Mo₂O₇ has the highest frequency value among the molybdate crystals, equal to 939 cm^–1. For the first time, Raman oscillation was obtained on a Na₂Mo₂O₇ crystal when excited by pulses of Nd:YLF laser with a wavelength of 1047 nm and a duration of 25 ps. The Raman gain coefficient at optimal orientation was 12.4 cm/GW, which is one of the highest values for solid-state Raman media. The described studies have shown that the sodium dimolybdate crystal is a promising nonlinear medium for creating a solid-state Raman converter.