Observation of Intense Second Harmonic Generation from MoS$_{2}$ Atomic Crystals

TL;DR

This paper reports highly efficient second harmonic generation in few-layer MoS2 crystals, revealing their symmetry and electronic structure, and opening new avenues for nonlinear optical applications in 2D materials.

Contribution

It demonstrates strong second harmonic generation in MoS2 and links the optical response to crystal symmetry and electronic properties, providing new insights into 2D material nonlinear optics.

Findings

Efficient second harmonic generation observed in odd-layer MoS2

Polarization dependence reveals crystal symmetry and orientation

Second-order susceptibility spectra inform about electronic structure

Abstract

Since de discovery of graphene, the family of 2-dimensional materials has attracted much recent attention. In this work, the nonlinear optical properties of few-layer MoS2 two-dimensional crystals are studied using femtosecond laser pulses. We observed highly efficient second harmonic generation from the odd-layer crystals, which shows a polarization intensity dependence that directly reveals the underlying symmetry and orientation of the crystal. Additionally, the measured second-order susceptibility spectra provide information about the electronic structure of the material. Our results open up new opportunities for studying the non-linear optical properties in these novel 2D crystals.