Diode pumped 560mJ 400Hz 10ns all-solid-state green MOPA system

A diode pumped Nd:YAG rod master-oscillator power-amplifier (MOPA) system that delivers pulse energy of 1.4J at 500Hz in a near top-hat beam distribution has been developed. The good beam quality (β) of 2.3 at 1064 µm is achieved by improving laser gain distribution in Nd:YAG rod amplifier module and optimizing the design of depolarization compensation. With a type II phase matched KTP crystal 560mJ pulse energy of green light is obtained under 70 MW/cm2 pump power density. The frequency conversion efficiency is about 40%. The beam quality (β) of the green light is 4.8.