Optical Parametric Amplification in Crossed Fabry‐Perot Cavities

Optical parametric amplification (OPA) is a promising method of producing extremely intense light. A new OPA scheme with comprehensively high performance is urgently required for future development. In this study, an amplification scheme known as crossed‐Fabry‐Perot‐cavity OPA (XOPA) is proposed. It is based on the principle of periodic idler elimination, which prevents energy back‐conversion among the three coupling waves, resulting in a monotonically increasing overall conversion efficiency. Using a signal at 808 nm and a pump at 532 nm, a chirped pulse XOPA is experimentally demonstrated with a conversion efficiency of 56.28% and a gain bandwidth of 120 nm. The measured pulse duration after compression is 19.2 fs, which is comparable to the Fourier‐transform‐limited 16.8 fs. Further investigations revealed several advantages. Stable pulse shaping in spatial, temporal, and frequency domains is realized by a spatiotemporally modulated pump. Pulse contrast adjustability on the front edge of the signal is verified in the XOPA of different Fabry‐Perot cavity lengths. These results indicate astringency and precise regulation of output in nonlinear processes. Considering numerous crystals suitable for noncollinear configurations from the near‐infrared to mid‐infrared regions, XOPA has a universal potential application in laser systems with extreme intensity, few‐cycle duration, and internal confinement fusion drivers. A Crossed‐Fabry‐Perot‐Cavity OPA (XOPA) scheme is proposed and experimentally demonstrated. The pump‐to‐signal conversion efficiency of up to 56.28% and gain bandwidth of 120 nm are simultaneously achieved with signal pulses at 808 nm and pump 532 nm. The excellent performance makes XOPA universal potential utilization in laser systems of extreme intensity, few‐cycle duration, and internal confinement fusion drivers.