High contrast amplification at 1053??nm limited by pulse stretching-compressing process

We report on our high-contrast laser based on high-contrast, high-energy seed injection, low-gain optical parametric chirped pulse amplification (OPCPA), and Nd:glass amplifiers, which can be used as the high-contrast front end of a high-power Nd:glass chirped pulse amplification (CPA) laser system. The energy of the stretched 1053 nm high-contrast seed pulse increases to 60 μJ by optimizing the frequency doubling crystal in the pulse cleaning device. After passing through a two-stage low-gain OPCPA, a 2-pass 2-rod Nd:glass amplifier, and a compressor the amplified pulse of 131 mJ/282 fs is achieved. The third-order correlation scanning measurement shows that the pulse contrast in the tens of ps range is about 10−7–10−8. With the high-contrast seed passing through the stretcher and compressor only, the contrast measurement indicates that the stretching-compressing process leads mainly to the contrast degradation of the amplified pulse.