Raman signal enhancement via a microring resonator

TL;DR

This paper demonstrates how a micro-ring resonator can significantly enhance Raman signals from graphene by trapping light and increasing local intensities, enabling improved non-linear optical signal detection.

Contribution

The study introduces the use of a doped silica micro-ring resonator to enhance Raman signals from graphene, showcasing its potential as a non-linear signal enhancer.

Findings

Raman signals from graphene are amplified inside the MRR.

Third harmonic generation was observed at 522 nm excitation.

Higher order Raman signals at 1597.6 nm were detected.

Abstract

Micro-ring resonators (MRRs) "trap" incoming light, and therefore, have been shown to achieve extremely high local intensities of light. Thus, they can be used to facilitate highly non-linear optical signals. By embedding materials that host non-linear optical processes inside the MRR, we expect to observe an enhancement in the strength of the non-linear optical signal. This concept is demonstrated here by extracting the Raman signature of graphene that is placed inside a MRR. A highly doped silica MRR which features an optical bus waveguide coupled to a loop (ring) tuned to near-infrared wavelengths is used. Raman signal with an excitation wavelength of 522 nm via third harmonic generation inside the MRR is observed. Higher order Raman signal of the embedded graphene at the 1597.6 nm excitation wavelength is also observed. This work demonstrates the feasibility of the MRR as a non-linear signal enhancer using novel MRR device setups.