Nonlinear metasurfaces can convert frequency and shape wavefronts in a single thin layer, but common geometric-phase designs act the same way across wavelengths. We show a thin-film lithium niobate metasurface whose response depends on the wavelength of the incident light. By spectrally tuning Mie-type resonances in two regions, we convert a Gaussian pump into a Hermite–Gaussian second-harmonic beam, while the pump itself passes through unchanged. For more details, find our paper here.
Our work on "Wavelength-Selective Nonlinear Wavefront Control in Resonant Thin-Film Lithium Niobate Metasurfaces" is now on Advanced Photonics Research (Wiley)!
Shaping second-harmonic light only at selected wavelengths.