Determination of the quasi-TE mode (in-plane) graphene linear absorption coefficient via integration with silicon-on-insulator racetrack cavity resonators

Abstract

We examine the near-IR light-matter interaction for graphene integrated cavity ring resonators based on silicon-on-insulator (SOI) racetrack waveguides. Fitting of the cavity resonances from quasi-TE mode transmission spectra reveal the real part of the effective refractive index for graphene, neff = 2.23 ± 0.02 and linear absorption coefficient, αgTE = 0.11 ± 0.01dBμm-1. The evanescent nature of the guided mode coupling to graphene at resosnance depends strongly on the height of the graphene above the cavity, which places limits on the cavity length for optical sensing applications. © 2014 Optical Society of America.