1 kHz, 511 mJ sub-nanosecond green laser via SHG of a slab-based MOPA system

We demonstrate a high pulse repetition frequency (PRF), high-energy sub-nanosecond green laser based on a conductively cooled end-pumped slab (CCEPS) MOPA as the fundamental laser source. In the fundamental stage, non-vacuum tube optics is firstly proposed by developing cylindrical lens based 1 dimensional 4-f imaging system in avoiding potential air breakdown during laser propagation. Three CCEPS based amplifiers are developed with maximum amplified energy of 1080 mJ, corresponding to a peak power of 1.48 GW. In the SHG stage, maximum green laser energy of 511 mJ with an instability of 1.7% and a pulse width of 697 ps is obtained at 1 kHz, corresponding to a peak power of 0.7 GW and a SHG efficiency is 47.2%. The results pave a way for achieving higher sub-nanosecond green laser energy at high PRF in a compact and feasible manner.