Millijoule ultrafast optical parametric amplification as replacement for high-gain regenerative amplifiers

We report on the development of an ultrafast optical parametric amplifier front-end for the Petawatt High Energy Laser for heavy Ion eXperiments (PHELIX) and the Petawatt ENergy-Efficient Laser for Optical Plasma Experiments (PEnELOPE) facilities. This front-end delivers broadband and stable amplification up to 1 mJ per pulse while maintaining a high beam quality. Its implementation at PHELIX allowed one to bypass the front-end amplifier, which is known to be a source of pre-pulses. With the bypass, an amplified spontaneous emission contrast of 4.9× 10⁻¹³ and a pre-pulse contrast of 6.2× 10⁻¹¹ could be realized. Due to its high stability, high beam quality and its versatile pump amplifier, the system offers an alternative for high-gain regenerative amplifiers in the front-end of various laser systems.