Advancing nonlinear nanophotonics: harnessing membrane metasurfaces for third-harmonic generation and imaging

Dielectric metasurfaces are crucial for enhancing optical nonlinear generation, particularly membrane metasurfaces with multipolar resonances and compact size. Investigating silicon dimer-hole membrane metasurfaces, Rahmani, and Xu show how bound states in the continuum (BICs) can be formed and transformed into quasi-BICs by adjusting hole gaps. This innovation enables efficient conversion of infrared images to visible range, promising applications in nonlinear photonics and near-infrared imaging technologies.