High and Stable Conversion Efficiency Obtaining in Single-Stage Multi-Crystal Optical Parametric Chirped Pulse Amplification System

Excess quantum noise in optical parametric chirped-pulse amplification

“…Intuition, based on the properties of laser and electrical amplifiers, suggests that saturation should suppress fluctuations. However, the effects of saturation on excess quantum noise lack a satisfactory description: while the experiments show degradation of pulse contrast during saturation [6,19], a numerical analysis of output statistics of PSF in an OPCPA seeded by a distributed classical noise source did not isolate the effect [20].…”

“…Henceforth, we refer to these phenomenological components observed at the output of an OPCPA as the coherent pulse and incoherent pedestal, respectively. Especially in the case of a broadband signal and high gain, a severe impact of PSF on noise performance is also well documented [5,6,19]: it both degrades the signal stability and places an upper limit on the extractable signal energy, due to transfer of pump energy to the incoherent pedestal. The dynamics of this energy transfer during amplification have not been observed yet: their understanding in the highly nonlinear saturation regime is not only of fundamental interest, but is particularly important with regard to performance, since amplifier saturation is necessary for obtaining good conversion efficiency and stable output energy.…”