# $\mathcal{P}\mathcal{T}$-Symmetric Coherent Perfect Absorber with Graphene

## TL;DR

This paper explores how integrating graphene sheets into $ ext{PT}$-symmetric coherent perfect absorbers enhances absorption, reduces gain requirements, and offers potential for improved CPA laser design through analytic modeling.

## Contribution

It provides exact analytic expressions for $ ext{PT}$-symmetric CPAs with graphene, highlighting how graphene parameters optimize absorption and reduce gain thresholds for CPA lasers.

## Key findings

- Graphene enhances absorption in CPA systems.
- Optimal parameters reduce the gain needed for CPA.
- Graphene's resonance effects improve CPA performance.

## Abstract

We investigate $\mathcal{PT}$-symmetric coherent perfect absorbers (CPAs) in the TE mode solution of a linear homogeneous optical system surrounded by graphene sheets. It is revealed that presence of graphene sheets contributes the enhancement of absorption in a coherent perfect absorber. We derive exact analytic expressions, and work through their possible impacts on lasing threshold and CPA conditions. We point out roles of each parameter governing optical system with graphene and show that optimal conditions of these parameters give rise to enhancement and possible experimental realization of a CPA laser. Presence of graphene leads the required gain amount to reduce considerably based on its chemical potential and temperature. We obtain that relation between system parameters decides the measure of CPA condition. We find out that graphene features contributing to resonance effect in graphene sheets are rather preferable to build a better coherent perfect absorber.