Optical Third-Harmonic Generation in Graphene

• Main Authors: Sung-Young Hong, Jerry I. Dadap, Nicholas Petrone, Po-Chun Yeh, James Hone, Richard M. Osgood, Jr.
• Format: Article
• Language: English
• Published: American Physical Society 2013-06-01
• Series: Physical Review X
• Online Access: http://doi.org/10.1103/PhysRevX.3.021014

We report strong third-harmonic generation in monolayer graphene grown by chemical vapor deposition and transferred to an amorphous silica (glass) substrate; the photon energy is in three-photon resonance with the exciton-shifted van Hove singularity at the M point of graphene. The polarization selection rules are derived and experimentally verified. In addition, our polarization- and azimuthal-rotation-dependent third-harmonic-generation measurements reveal in-plane isotropy as well as anisotropy between the in-plane and out-of-plane nonlinear optical responses of graphene. Since the third-harmonic signal exceeds that from bulk glass by more than 2 orders of magnitude, the signal contrast permits background-free scanning of graphene and provides insight into the structural properties of graphene.