Tunable third harmonic generation based on high-Q polarization-controlled hybrid phase-change metasurface

Dielectric metasurfaces have made significant advancements in the past decade for enhancing light-matter interaction at the nanoscale. Particularly, bound states in the continuum (BICs) based on dielectric metasurfaces have been employed to enhance nonlinear harmonic generation. However, conventional nonlinear metasurfaces are typically fixed in their operating wavelength after fabrication. In this work, we numerically demonstrate tunable third harmonic generation (THG) by integrating a dielectric metasurface with the phase-change material Ge