# Coherent anti-Stokes Raman Spectroscopy of single and multi-layer graphene

## TL;DR

This paper demonstrates the use of Coherent anti-Stokes Raman Spectroscopy (CARS) to analyze the vibrational properties of single and multi-layer graphene, highlighting methods to suppress background noise for clearer spectral measurements.

## Contribution

It introduces a technique to measure the vibrationally resonant CARS peak in graphene by reducing pulse overlap, improving vibrational sensitivity in imaging.

## Key findings

- CARS signal dominated by non-resonant background obscures Raman lineshape.
- Reducing laser pulse overlap suppresses the non-resonant background.
- CARS can be effectively used for vibrational imaging of graphene.

## Abstract

We report stimulated Raman spectroscopy of the G phonon in both single and multi-layer graphene, through Coherent anti-Stokes Raman Scattering (CARS). The signal generated by the third order nonlinearity is dominated by a vibrationally non-resonant background (NVRB), which obscures the Raman lineshape. We demonstrate that the vibrationally resonant CARS peak can be measured by reducing the temporal overlap of the laser excitation pulses, suppressing the NVRB. We model the observed spectra, taking into account the electronically resonant nature of both CARS and NVRB. We show that CARS can be used for graphene imaging with vibrational sensitivity.