Efficient noncollinear optical parametric chirped-pulse amplification in oversaturation region

Abstract

Optical parametric chirped pulse amplification (OPCPA) is the workhorse to generate intense ultrashort pulses across a broad wavelength range. Typically, OPCPA operates in the saturation region, but barely in the oversaturation region due to efficiency drop caused by back conversion. Through numerical simulations, we reveal the potential of noncollinear OPCPA to achieve significantly higher conversion efficiency in the oversaturation regime compared to the recognized saturation efficiency. This enhancement stems from the suppression of back conversion facilitated by noncollinearity-induced idler dissipation. Besides offering high efficiency and robustness, the oversaturated noncollinear OPCPA also exhibits acceptable spatial and temporal properties, as well as spatiotemporal coupling properties. These findings hold promise for enhancing the final stage of a noncollinear OPCPA system, where a high conversion efficiency is essential.