Introducing Corrections to the Reflectance of Graphene by Light Emission

TL;DR

This paper develops a transfer matrix model to analyze light emission from multilayer graphene, revealing significant coherent emission effects that alter reflectance and suggest potential laser applications.

Contribution

It introduces a novel formulation for the light emission properties of multilayer graphene, accounting for coherent emission effects not previously considered.

Findings

Quantitative explanation of multilayer graphene contrast on substrates.

Identification of sizable corrections to reflectance due to coherent emission.

Multilayer graphene acts as a partial coherent light source with potential laser applications.

Abstract

Monolayer graphene absorbs 2.3 percent of the incident visible light. This 'small' absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method's validity experimentally. We could quantitatively explain the measured contrasts of multilayer graphene on SiO$_2$/Si substrates and found sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.