High-power, continuous-wave, optical parametric oscillator pumped by an optically pumped semiconductor laser at 532 nm

We report a high-power, cw, single-frequency optical parametric oscillator pumped external to an optically pumped semiconductor laser (OPSL). The singly resonant oscillator (SRO), based on a 30 mm crystal of MgO:sPPLT, is pumped by a 6 W, cw OPSL at 532 nm. By deploying signal outcoupling and loose focusing in the presence of low pump power, we achieve significant improvements in SRO performance across the tuning range with regard to signal power, extraction efficiency, and pump depletion by reducing thermal effects. We generate >1.78 Wof idler and >0.9 Wof signal over 856-1404 nm while maintaining a total output power of >2 W over 93% of the tuning range at an extraction efficiency of 48.7% and pump depletion of 84%. The signal power remains within 0.85-1.05 W across the entire tuning range and has a TEM(00) spatial profile with M(2) < 1.28 and circularity of > 97%. Measurements of signal spectrum confirm single-frequency performance with an instantaneous linewidth of similar to 15 MHz and frequency stability better than 60 MHz over 60 s. (C) 2010 Optical Society of America