Discretely tuned radiation generation via stimulated Raman scattering in Ba(NO3)2 crystal

Abstract

SRS of the neodymium laser radiation in the ion-molecular crystals provides of the discrete set of radiation wavelengths, including, in particular, the emission in the eye-safe range of spectrum. This paper is devoted to study of SRS in barium nitrate [1] (Δω=1046 cm–1) of the multi mode radiation of lasers on YAG:Nd and KGT:Nd. The pump was focused into the crystal with the length of 8 cm by the lens with the focal length of 19 cm. In the Fig. 1 are shown the dependencies of the pump energy conversion efficiency (λp1 = 1.064 µm and λp2= 1.067 µm) to the SRS components. The spectrum width in this experiment equaled Δνp1=0.5 cm–1 (YAG) and Δνp2=l-8 cm–1 (KGT), pulse duration was 10 ns, beam diameter - 5 mm and its divergence - 6′. The maximal conversion efficiency to the first stokes component (λ=1.2 µm) was limited by the excitation of the second stokes component (λ=1.37 µm) at the level of 40 % for both variants of the pump. Opposite directed generation was observed only in the case of pumping by YAG laser. That is why in this case the rate of the conversion to the first stokes component efficiency growth was lower. The maximal total conversion efficiency equaled ~63% for the pumping energy of 10.. 15 mJ for KGT laser.