Different schemes of parametric amplification (PA), aimed at designing a source of femtosecond near-IR (1.3 – 2.2 μm) radiation, are compared by solving a system of truncated equations describing three-wave mixing. A terawatt Ti : sapphire laser with an energy of 60 mJ and a pulse duration of 50 fs is used as a pump source for PA schemes. The dependences of the output energies, pulse durations, and spectral widths of signal and idler waves on the BBO crystal length for two types of phase matching and on the group-delay dispersions for the pump and signal waves is investigated. It is shown that in the case of direct PA, using a type-II phase-matching BBO crystal of optimal length, one can obtain signal (1.333 μm) and idler (2 μm) waves with pulse durations of 34 and 32 fs, respectively, with a total energy conversion efficiency up to 40 %. The application of double chirping scheme increases the total conversion efficiency to 60 %; however, the spectral width of generated pulses decreases. The spectral width can only be increased by reducing the conversion efficiency. In this case, a more simple and compact solution is the scheme of direct PA with a transform-limited pump pulse.

通过求解描述三波混频的截断方程系统，比较了不同的参数放大 (PA) 方案，旨在设计飞秒近红外 (1.3 – 2.2 μm) 辐射源。能量为 60 mJ 且脉冲持续时间为 50 fs 的太瓦 Ti：蓝宝石激光器用作 PA 方案的泵浦源。研究了信号和闲散波的输出能量、脉冲持续时间和光谱宽度对两种相位匹配的 BBO 晶体长度以及泵浦波和信号波的群延迟色散的依赖性。结果表明，在直接 PA 的情况下，使用最佳长度的 II 型相位匹配 BBO 晶体，可以获得脉冲持续时间分别为 34 和 32 fs 的信号（1.333 μm）和闲散（2 μm）波，总能量转换效率高达40%。双线性调频方案的应用使总转换效率提高到60%；然而，产生的脉冲的频谱宽度会减小。只能通过降低转换效率来增加谱宽。在这种情况下，更简单和紧凑的解决方案是具有变换受限泵浦脉冲的直接 PA 方案。