2019/04/12 by Qingchen Yuan, Liang Fang, Yuan, Qingchen +12
Engineering · Materials Science · #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Plasmonic and Surface Plasmon Research #Thermal Radiation and Cooling Technologies
paper · pdf · doi:10.48550/arxiv.1904.06027
openalex publication_date 2019/04/12 · openalex created_date 2019/04/25 · openalex updated_date 2026/07/31
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.