We investigate linear and nonlinear spectral singularities in the transverse electric and transverse magnetic modes of a slab laser consisting of an active planar slab sandwiched between a pair of graphene or Weyl semimetal thin sheets. The requirement of the presence of linear spectral singularities gives the laser threshold condition while the existence of nonlinear spectral singularities due to an induced weak Kerr nonlinearity allows for computing the laser output intensity in the vicinity of the threshold. The presence of the graphene and Weyl semimetal sheets introduces additional physical parameters that we can use to tune the output intensity of the laser. We provide a comprehensive study of this phenomenon and report peculiarities of lasing in the transverse magnetic (TM) modes of the slab with Weyl semimetal coatings. In particular, we reveal the existence of a critical angle such that no lasing seems possible for TM modes of the slab with the smaller emission angle. Our results suggest that for TM modes with an emission angle slightly exceeding the critical angle, the laser output intensity becomes highly sensitive to the physical parameters of the coating.

中文翻译：

---

光谱奇异性和带有2D材料涂层的可调平板激光器

我们研究了由一个有源平面平板夹在一对石墨烯或Weyl半金属薄板之间的平板激光器的横向电磁模式中的线性和非线性光谱奇点。存在线性光谱奇点的要求给出了激光阈值条件，而由于感应的弱的Kerr非线性而导致的非线性光谱奇点的存在允许计算阈值附近的激光输出强度。石墨烯和Weyl半金属片的存在引入了其他物理参数，我们可以使用这些参数来调整激光器的输出强度。我们提供了对此现象的全面研究，并报告了带有Weyl半金属涂层的平板在横向磁（TM）模式下的激光发射特性。尤其是，我们揭示了临界角的存在，使得对于发射角较小的平板的TM模式似乎没有激光发射的可能。我们的结果表明，对于发射角略大于临界角的TM模式，激光输出强度对涂层的物理参数高度敏感。