High-Stability High-Energy Picosecond Optical Parametric Chirped Pulse Amplifier as a Preamplifier in Nd:Glass Petawatt System for Contrast Enhancement
1National Laboratory on High Power Laser and Physics, Shanghai 201800 2Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and fine Mechanics, Chinese Academy of Science, Shanghai 201800 3University of Chinese Academy of Sciences, Beijing 100049
Abstract:We demonstrate a novel picosecond optical parametric preamplification to generate high-stability, high-energy and high-contrast seed pulses. The 5 ps seed pulse is amplified from 60 pJ to 300 $\mu$J with an 8.6 ps/ 3 mJ pump laser in a signal stage of short pulse non-collinear optical parametric chirped pulse amplification. The total gain is more than 10$^{6}$ and the rms energy stability is under 1.35%. The contrast ratio is higher than 10$^{8}$ within a scale of 20 ps before the main pulse. Consequently, the improvement factor of the signal contrast is approximately equal to the gain 10$^{6}$ outside the pump window.