0.43 J/100 ps Nd:YAG laser with adaptive compensation of thermally induced lens

We demonstrate a diode-pumped master oscillator power amplifier Nd:YAG 1064 nm laser with sub-joule-level output energy of 0.43 J, high pulse repetition rate of 200 Hz, and short pulse duration of 100 ps. The 5 mJ master oscillator consisted of a 100 nJ/100 ps Nd:YVO4 microchip laser and end-pumped Nd:YAG regenerative amplifier. The two-pass output amplifier was based on two ∅10×140  mm Nd:YAG laser rods. We apply an adaptive compensator with an analyzer based on an astigmatic optical system and a quadrant photodiode to compensate for low-order wave-front non-stationary thermal distortions in a high-energy laser amplifier. The adaptive compensator demonstrates high sensitivity to curvature changes of λ/100, and it provides output beam divergence near 1.5×DL in 100 ps 0.43  J×200  Hz of operation mode.