基于角色散的非共线匹配宽带三倍频技术

宽带光打靶可以有效降低激光等离子体相互作用过程中非线性效应。提出一种基于角色散的非共线匹配宽带三倍频方案，利用宽带基频与窄带二倍频的非共线和频产生宽带三倍频，和频过程中通过特殊设计的渐变光栅实现不同频率的基频光束以特定角度入射，补偿了波长差异引入的位相失配使得全波段满足位相匹配条件。理论模拟表明，采用KDP晶体Ⅱ类位相匹配，将中心波长为1058 nm、带宽10 nm的宽带基频光与526.5 nm的二倍频光进行非共线匹配和频，可以实现高效宽带三倍频转换。

Noncollinear matched broadband third-harmonic generation based on angular dispersion

Broadband laser can effectively reduce the nonlinear effect in the process of laser plasma interaction. This paper proposes a noncollinear matching broadband third-harmonic generation based on angular dispersion, which uses the noncollinear sum frequency of the broadband fundamental wave and the narrowband second harmonic to generate broadband third harmonic, and the sum frequency process is realized by a specially designed gradient grating. The fundamental laser beams of different frequencies are incident at a specific angle, which compensates for the phase mismatch caused by the wavelength difference, so that the whole waveband meets the match condition of phase. Theoretical simulation shows that using KDP crystal type II phase matching, high efficiency broadband third-harmonic generation can be achieved by combining the broad-band fundamental wave (center wavelength 1058 nm, bandwidth 10 nm) and the second harmonic (526.5 nm).