In this work we probe the third-order non-linear optical property of graphene, hexagonal boron nitride and their heterostructure by the use of coherent anti-Stokes Raman Spectroscopy. When the energy difference of the two input fields match the phonon energy, the anti-Stokes emission intensity is enhanced in h-BN, as usually expected while for graphene a anomalous decrease is observed. This behaviour can be understood in terms of q coupling between the electronic continuum and a discrete phonon state. We have also measured a graphene/h-BN heterostructure and demonstrate that the anomalous effect in graphene dominates the heterostructure optical response.
@article{arxiv.1701.09023,
title = {Anomalous Non-linear Optical Response Of Graphene Near Phonon Resonances},
author = {Lucas Lafetá and Alisson Cardore and Thiago G. Mendes Sá and Kenji Watanabe and Takashi Taniguchi and Leonardo C. Campos and Ado Jorio and Leandro M. Malard},
journal= {arXiv preprint arXiv:1701.09023},
year = {2020}
}