Experimentation of Tunable All-Solid-State Laser Producing4～5 μm Radiation

An all-solid-state LiIO_3 difference frequency generator(DFG),pumped by a singly resonant KTP optical parametric oscillator(OPO) pumped by the second harmonic of a pulsed Nd∶YAG laser,which have a pulse width of 12 ns and pulse energy of 300 mJ,operating at(1.064 μm) and the fundamental frequency Nd∶YAG laser,is experimentally demonstrated and analyzed.The maximum frequency-doubling conversion efficiency is 66.7%;quantum conversion efficiency of KTP OPO is 50%;the quantum conversion efficiency of difference frequency generator is 1.5%,and 100 μJ energy of single pulse is achieved at 4.45 μm wavelength.The frequency tuning range is 4.1～4.5 μm.The beam divergence is 12 mrad in vertical direction and 4 mrad in horizontal direction.