Kuzmin I V, Mironov S Yu, Martyanov M A, Potemkin A K, Khazanov E A
Appl Opt. 2021 Apr 10;60(11):3128-3135. doi: 10.1364/AO.422601.
A method for highly efficient fourth harmonic generation (FHG) retaining spatiotemporal intensity distribution of broadband chirped laser pulses is proposed. It is based on the use of pulses with linear frequency chirps of equal absolute magnitudes and opposite signs at the oo-e type noncollinear second harmonic generation. Fourth harmonic generation can by obtained by the classical method, since the second harmonic pulse is narrowband and spectrally limited. A possibility to retain the three-dimensional (3D) structure of the field at FHG with a conversion efficiency ∼60 is demonstrated by the numerical simulation of 3D pulses with a quasi-ellipsoidal intensity distribution.
提出了一种高效产生四阶谐波（FHG）并保留宽带啁啾激光脉冲时空强度分布的方法。该方法基于在oo - e型非共线二次谐波产生中使用具有相等绝对幅度和相反符号的线性频率啁啾脉冲。由于二次谐波脉冲是窄带且受光谱限制的，因此可以通过经典方法获得四阶谐波。通过对具有准椭球强度分布的三维脉冲进行数值模拟，证明了在四阶谐波产生时保留场的三维（3D）结构且转换效率约为60%的可能性。
