High average-power 2 mu m radiation generated by intracavity KTP OPO

摘要

A high average-power 2 mu m laser with good beam quality based on an intracavity potassium titanium oxide phosphate (KTP) optical parametric oscillator (OPO) is demonstrated. A concave lens is used in the 1064 nm Nd:YAG pumped laser cavity to compensate for the thermal lensing of the laser rod. The cavity length of the KTP OPO is enlarged to improve the 2 mu m beam quality. The maximum average output of the 2 mu m laser is up to 18 W at 7 kHz with M-2 less than 6 and pulse width of 70 ns. The FWHM of the signal and idle lights are both less than 3 nm.