The process of frequency doubling of the first type of interaction (oo-e) of intense short laser pulses in crystals with a regular domain structure was numerically studied. The influences of the group-velocity dispersion of the medium to the third order and Kerr-type cubic nonlinearity on the formation of the second harmonic pulse were analyzed. The case where the conditions of quasi-phase matching and group-velocity synchronism were both simultaneously satisfied was considered. In this case, an insignificant change in the domain size from the exact value providing the quasi-phase matching condition was shown to lead to a significant increase in the efficiency (almost double) of second harmonic generation. Calculations showed that the latter was due to mutual compensation of phase shifts caused by Kerr-type cubic nonlinearity, the dispersion of the medium, and the additional value of the wavenumber of the nonlinear grating. Lithium niobate with 5% added MgO (5% MgO:LiNbO₃) was chosen as a periodically polarized crystal in which the conditions of quasi-phase matching and group-velocity synchronism could be created at a certain wavelength of fundamental radiation (~1560 nm).

数值研究了强短激光脉冲在具有规则畴结构的晶体中的第一类相互作用（oo-e）的倍频过程。分析了介质的三阶群速度色散和克尔型三次非线性对二次谐波脉冲形成的影响。考虑同时满足准相位匹配和群速度同步条件的情况。在这种情况下，域大小与提供准相位匹配条件的精确值相比发生微不足道的变化会导致二次谐波生成效率的显着提高（几乎翻倍）。计算表明，后者是由于克尔型三次非线性引起的相移相互补偿，介质的色散和非线性光栅波数的附加值。添加了 5% MgO 的铌酸锂（5% MgO:LiNbO₃ ) 被选为周期性极化晶体，其中可以在特定波长的基本辐射 (~1560 nm) 下创建准相位匹配和群速度同步的条件。