Frequency up-conversion of infrared radiation in AlGaAs-on-insulator nonlocal metasurface

The ability to detect near infrared light has important applications in telecoms, medical diagnostics and remote sensing. Traditional free-space up-conversion systems based on bulk crystals are not suitable for integration purposes, due to their large footprint. Here, we employ a nonlocal dielectric metasurface as an ultra-thin up-converter, by exploiting quasi-bound states in the continuum to increase the conversion efficiency of the nonlinear process.