量子级联激光器（Quantum Cascade Laser，QCL）是依赖电子在量子阱子带间跃迁辐射出光子而发生激射的单极型半导体激光器。大量的理论与实验研究已经证明轻微的外部扰动（如光反馈、光注入）或内部足够强的非线性模式耦合能够引起半导体激光器的非线性输出。QCL作为新型半导体器件，具有腔内强度高、子带间光学非线性强以及电子弛豫时间快等特点，激发了学者研究其非线性动力学的兴趣。本文详细综述了QCL的非线性动态特性研究进展情况，探究了QCL非线性动力学性质的产生机理，总结了QCL非线性特性的应用场景。

Ultrafast laser pulses provide unique tools to manipulate magnetization dynamics at femtosecond timescales, where the interaction of the electric field usually dominates over the magnetic field. Recent proposals using structured laser beams have demonstrated the possibility to produce regions where intense oscillating magnetic fields are isolated from the electric field. In these conditions, we show that technologically feasible tesla-scale circularly polarized high-frequency magnetic fields induce purely precessional nonlinear magnetization dynamics. This fundamental result not only opens an avenue in the study of laser-induced ultrafast magnetization dynamics, but also sustains technological implications as a route to promote all-optical non-thermal magnetization dynamics both at shorter timescales – towards the sub-femtosecond regime – and at THz frequencies.

We demonstrate experimentally that mid-infrared quantum cascade lasers (QCLs) operating under external optical feedback exhibit extreme pulses. These events can be triggered by adding small amplitude periodic modulation, with the highest success rate for the case of a pulse-up excitation. These findings broaden the potential applications for QCLs, which have already been proven to be a semiconductor laser of interest for spectroscopic applications and countermeasure systems. The ability to trigger extreme events paves the way for optical neuron-like systems where information propagates as a result of high intensity bursts.