After the introduction of the ionization-injection scheme in laser wake field acceleration and of related high-quality electron beam generation methods, such as two-color and resonant multi-pulse ionization injection (ReMPI), the theory of thermal emittance has been used to predict the beam normalized emittance obtainable with those schemes. We recast and extend such a theory, including both higher order terms in the polynomial laser field expansion and non-polynomial corrections due to the onset of saturation effects on a single cycle. Also, a very accurate model for predicting the cycle-averaged distribution of the extracted electrons, including saturation and multi-process events, is proposed and tested. We show that our theory is very accurate for the selected processes of ${\mathrm{Kr}}^{8^{+}\to {10}^{+}}$ and ${\mathrm{Ar}}^{8^{+}\to {10}^{+}}$ , resulting in a maximum error below 1%, even in a deep-saturation regime. The accurate prediction of the beam phase-space can be implemented, for example, in laser-envelope or hybrid particle-in-cell (PIC)/fluid codes, to correctly mimic the cycle-averaged momentum distribution without the need for resolving the intra-cycle dynamics. We introduce further spatial averaging, obtaining expressions for the whole-beam emittance fitting with simulations in a saturated regime, too. Finally, a PIC simulation for a laser wakefield acceleration injector in the ReMPI configuration is discussed.

为研究多脉冲激光的热累积效应对硼掺杂纳米硅薄膜熔覆过程的影响，采用单温模型，利用三维有限元方法对激光与硅薄膜的相互作用过程中温度场的分布进行了数值模拟，得到了多脉冲激光耦合情况下的温度场变化规律。仿真结果表明：与单脉冲相比，在多脉冲激光作用下，峰值温度增加了3.2%，熔池尺寸扩大了18.75%，同时热影响区范围也明显增加；激光辐照后，熔覆层表面温度下降，但基体温度仍会继续上升，多脉冲热累积效应为纳米硅薄膜中硼元素扩散提供了有利条件。最后，通过单脉冲及多脉冲激光熔覆实验，分析了熔覆硅薄膜后的熔覆层表面状况的差异，并获得了激光熔覆辅助硼元素扩散的一般规律，为硼掺杂纳米硅薄膜的激光辅助扩散技术在半导体器件中的应用提供了条件。

针对远距离飞机目标，机载多脉冲激光测距机通常采用数字化处理体制，影响其测距精度的因素包括发射激光脉冲宽度的距离分辨率、大气传播及目标反射特性造成的波形展宽、回波信号接收处理通道的非线性相频特性等。数字化采样率、回波信号降噪、目标峰值点位置估计等数字化处理过程引起较大的目标距离定位误差。提出了基于经验模态分解（Empirical Mode Decomposition，EMD）和重构的回波降噪方法，首先对脉冲激光目标回波波形进行建模，然后分析了现有数字化回波降噪算法的性能及其对定位精度的影响。实验结果表明，所提方法可以准确提取目标峰值点位置，改善激光测距机的目标定位精度。

报道了多脉冲机制泵浦KGW晶体的皮秒红外多波长拉曼激光器。建立数学模型研究了多脉冲泵浦机制对拉曼活性分子振动模式的影响，模拟结果显示了拉曼活性分子对多脉冲泵浦机制的响应相比于传统的单脉冲泵浦机制更加活跃与持久，从而促进衰减的分子振荡多次回到本征振动频率。多脉冲的增强效果有利于改善拉曼增益，降低拉曼阈值，提高拉曼转换效率。设计了皮秒多脉冲泵浦KGW拉曼晶体实验，结果表明，三脉冲泵浦机制将拉曼增益改善了2倍以上，拉曼阈值降低了50%以上，768 cm^–1和901 cm^–1拉曼模式的转换效率分别提高了16%和22%以上。基于三脉冲泵浦机制，设计了1 kHz毫焦级皮秒多脉冲泵浦KGW晶体红外多波长拉曼激光器，对于768 cm^–1和901 cm^–1两个振动模式，获得脉冲能量分别为1.39 mJ和1.38 mJ，最大拉曼转换效率分别为29.6%和25.7%。此外，对于两种拉曼模式，此拉曼激光器都可以同时输出多达8条红外拉曼光谱，涵盖范围800~1 700 nm。