Coherent absorption of light by graphene and other optically conducting surfaces in realistic on-substrate configurations

S Zanotto,F Bianco,D Convertino,A Tredicucci,V Miseikis,C Coletti

doi:10.1063/1.4967802

Abstract

Analytical formulas are derived describing the coherent absorption of light from a realistic multilayer structure composed by an optically conducting surface on a supporting substrate. The model predicts two fundamental results. First, the absorption regime named coherent perfect transparency theoretically can always be reached. Second, the optical conductance of the surface can be extrapolated from absorption experimental data even when the substrate thickness is unknown. The theoretical predictions are experimentally verified by analyzing a multilayer graphene structure grown on a silicon carbide substrate. The graphene thickness estimated through the coherent absorption technique resulted in good agreement with the values obtained by two other spectroscopic techniques. Thanks to the high spatial resolution that can be reached and high sensitivity to the probed structure thickness, coherent absorption spectroscopy represents an accurate and non-destructive diagnostic method for the spatial mapping of the optical properties of two-dimensional materials and of metasurfaces on a wafer scale.

Highlights

Optics of conducting surfaces has experienced in the past decade major breakthroughs
A technique for nondestructive wafer scale diagnosis of optically conducting surfaces is enabled. This technique has a remarkable potential for instance when considering multilayer graphene sheets, whose thickness determination is necessary for applications in optics[17,18,19,20] and electronics.[21,22,23]
Low-energy electron microscopy (LEEM) determines the graphene number of layers from the quantized oscillations in the electron reflectivity, but its application is generally restricted to conductive substrates and its reliability is limited up to 10 layers.[24]

Summary

Introduction

Optics of conducting surfaces (i.e., surfaces displaying mainly real ac conductivity at the frequencies considered) has experienced in the past decade major breakthroughs. Coherent absorption of light by graphene and other optically conducting surfaces in realistic on-substrate configurations

Results

Conclusion