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arXiv · 1904.06027

Second harmonic and sum-frequency generations from a silicon metasurface integrated with a two-dimensional material

Qingchen Yuan·Liang Fang·Hanlin Fang·Juntao Li·Tao Wang·Wanqi Jie·Jianlin Zhao·Xuetao Gan
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Abstract

Silicon-based nonlinear metasurfaces were implemented only with third-order nonlinearity due to the crystal centrosymmetry and the efficiencies are considerably low, which hinders their practical applications with low-power lasers. Here, we propose to integrate a two-dimensional GaSe flake onto a silicon metasurface to assist high-efficiency second-order nonlinear processes, including second-harmonic generation (SHG) and sum-frequency generation (SFG). By resonantly pumping the integrated GaSe-metasurface, which supports a Fano resonance, the obtained SHG is about two orders of magnitude stronger than the third-harmonic generation from the bare silicon metasurface. In addition, thanks to the resonant field enhancement and GaSe's strong second-order nonlinearity, SHG of the integrated structure could be excited successfully with a low-power continuous-wave laser, which makes it possible to further implement SFG. The high-efficiency second-order nonlinear processes assisted by two-dimensional materials present potentials to expand silicon metasurface's functionalities in nonlinear regime.

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Qingchen Yuan, Liang Fang, Hanlin Fang, Juntao Li, Tao Wang, Wanqi Jie, Jianlin Zhao, Xuetao Gan. 2019-04-12. Second harmonic and sum-frequency generations from a silicon metasurface integrated with a two-dimensional material. https://arxiv.org/abs/1904.06027

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