Characteristics of a side pumped tungstate Raman laser

An investigation of a crystalline Raman laser pumped perpendicular to the Raman resonator axis is reported. A rectangular prism of potassium gadolinium tungstate crystal is pumped at 90° to the Raman laser axis using a line focused 532 nm pump laser of pulse duration 10 ns. The Raman laser threshold was 6.1 mJ and at 12 mJ pump energy a maximum output energy of 2.7 mJ was obtained with a slope efficiency of 46%. The threshold is compared with theoretical predictions, which suggest that gain and laser threshold are largely independent of pump direction. The results highlight significant potential for Raman lasers with enhanced degrees of flexibility and increased power.