Ultrafast Optical Modulation of Harmonic Generation in Two-Dimensional Materials

作者：Yang Cheng, Hao Hong, Hui Zhao, Chunchun Wu, Yu Pan, Can Liu, Yonggang Zuo, Zhihong Zhang, Jin Xie, Jinhuan Wang, Dapeng Yu, Yu Ye, Sheng Meng, Kaihui Liu · 发表于：Nano Letters · 年份：2020 · DOI：10.1021/acs.nanolett.0c02972 · 被引用次数：47 · 研究领域：Advanced Fiber Laser Technologies、Photonic and Optical Devices、Mechanical and Optical Resonators

The modulation of optical harmonic generation in two-dimensional (2D) materials is of paramount importance in nanophotonic and nano-optoelectronic devices for their applications in optical switching and communication. However, an effective route with ultrafast modulation speed, ultrahigh modulation depth, and broad operation wavelength range is awaiting a full exploration. Here, we report that an optical pump can dynamically modulate the third harmonic generation (THG) of a graphene monolayer with a relative modulation depth above 90% at a time scale of 2.5 ps for a broad frequency ranging from near-infrared to ultraviolet. Our observation, together with the real-time, time-dependent density functional theory (TDDFT) simulations, reveals that this modulation process stems from nonlinear dynamics of the photoexcited carriers in graphene. The superior performance of the nonlinear all-optical modulator based on 2D materials paves the way for its potential applications including nanolasers and optical communication circuits.