Влияние фокусировки на нестационарное ВКР 0.3 ps лазерных импульсов в кристалле BaWO-=SUB=-4-=/SUB=- с самозаправкой ФСМ

Abstract

The effect of focusing, taking into account self-focusing, on the interference of SRS (stimulated Raman scattering) and self-phase modulation in a 8-mm BaWO4 crystal pumped by laser pulses with a duration of 0.3 ps and a wavelength of 515 nm is experimentally studied. The maximum efficiency of SRS conversion (~23%) to the Stokes component of the ν1 = 925 cm–1 strongest mode is obtained with a lens with a focal length of 40 mm at the linear focus shift towards the rear facet of the crystal. The increase in efficiency, when the linear focus is shifted to the rear facet, is associated with an increase in the distance between the linear and nonlinear foci, which results in an increase in the effective length of the nonlinear interaction.