Spectral singularities and tunable slab lasers with 2D material coating

TL;DR

This paper explores how 2D material coatings like Graphene and Weyl semimetals can be used to tune the spectral singularities and output intensity of slab lasers, revealing critical angles and parameter sensitivities.

Contribution

It introduces a novel analysis of spectral singularities in slab lasers with 2D material coatings, including nonlinear effects and tunability of laser output.

Findings

Spectral singularities determine laser threshold conditions.

Weyl semimetal coatings introduce tunable parameters for laser control.

A critical emission angle affects the lasing capability of TM modes.

Abstract

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 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 smaller emission angle. Our results suggest that for TM modes with emission angle slightly exceeding the critical angle, the laser output intensity becomes highly sensitive to the physical parameters of the coating.