High-efficiency infrared upconversion imaging with nonlinear silicon metasurfaces empowered by quasi-bound states in the continuum

Infrared imaging is indispensable for its ability to penetrate obscurants and visualize thermal signatures, yet its practical use is hindered by the intrinsic limitations of conventional detectors. Nonlinear upconversion, which converts infrared light into the visible band, offers a promising pathway to address these challenges. Here, we demonstrate high-efficiency infrared upconversion imaging using nonlinear silicon metasurfaces. By strategically breaking in-plane symmetry, the metasurface supports a high-Q quasi-bound states in the continuum resonance, leading to strongly enhanced third-harmonic generation (THG) with a conversion efficiency of 3×10−5 at a pump intensity of 10 GW/cm2. Through this THG…

• NT
  Nottingham Trent University
• TU
  Trent University
• NN
  National Natural Science Foundation of China

  Awards: 12304420, 12264028, 12104105, 12364045, 12364049
• NS
  Natural Science Foundation of Jiangxi Province

  Awards: 20232BAB211025, 20242BAB25041, 20232BAB201040