非线性晶体三波互作用允许参量的修正计算

Amendatory Calculation of the Acceptance Parameters in Three-Wave Interactions

采用传统级数展开方法计算晶体非线性三波互作用的允许参量。利用定义通过计算机数值模拟进行了精确计算 ,修正了传统计算结果 ,发现晶体在产生二次谐波时 ,在某些角度存在很宽的允许波长峰 ,超过传统文献值约几十倍。研究表明 ,在产生二次谐波时 ,10mm长的晶体在某些波段获得 10 0nm以上的允许倍频带宽是可能的 ,并提出了移动这些宽带的方法。

The traditional method of calculation for the acceptance parameters by Taylor expansion in three-wave interactions is only suitable for the condition of small acceptance parameters. The accurate calculation method of the acceptance parameters by means of definition was given. Through numerical calculation some values of acceptance parameters were corrected, and some super wide acceptance spectral bands of SHG (second harmonic generation) in nonlinear crystals were found, which are almost tens of times larger than that calculated by traditional method. It suggests the possibility of obtaining super wide acceptance spectral bands in 1 cm long crystal for SHG.