Tunable lasers in the terahertz frequency range are of great demand for many spectroscopic applications. The first continuously tunable p-Ge Landau level terahertz laser had the drawback of pulsed operation at very low temperatures. There have been promising developments of Landau level lasers based on graphene in combination with other two-dimensional materials. Extended theoretical work has resulted in an understanding of carrier dynamics and the relevant Auger and phonon processes. Both optical and electrical pumping schemes have been proposed to achieve inversion and lasing. There are still open questions about the combination of two-dimensional structures and the carrier transfer mechanisms between the layers. By solving the technological challenges, the realization of a near room-temperature Landau level laser can be envisaged.

太赫兹频率范围内的可调谐激光器对许多光谱应用都有很大的需求。第一个连续可调 p-Ge Landau 级太赫兹激光器的缺点是在非常低的温度下进行脉冲操作。基于石墨烯结合其他二维材料的朗道能级激光器已经取得了有希望的发展。扩展的理论工作导致了对载流子动力学和相关俄歇和声子过程的理解。已经提出了光和电泵浦方案来实现反转和激光发射。关于二维结构的组合和层间载流子转移机制仍然存在悬而未决的问题。通过解决技术挑战，可以设想实现接近室温的朗道级激光器。