Optical parameter oscillator for extremely pumped alkali vapor lasers

An optical parameter oscillator (OPO) based on a Nd:YAG laser and two pieces of KTiOPO4 (KTP) nonlinear crystal that could be tuned from 750-800 nm was built for alkali vapor lasers high-intensity pumping experiment. It can provide 113 mJ each pulse at the central wavelength of 780.2 nm with a duration of 15.43 ns. This means the peak power could be as high as 7 MW. The spectral line width is about 0.38 nm and the beam diameter is 5.5 mm. Clear fluorescence can be observed when the signal light passes through the 10 cm long Rb cell with Ar buffer gas at a temperature of 120 ℃, which demonstrates the validity of this OPO system to be used in alkali laser studies.