Experimental demonstration of second-harmonic generation in high ?² metasurfaces

Metasurfaces able to concentrate light at various wavelengths are promising for enhancing nonlinear interactions. In this Letter, we experimentally demonstrate infrared second-harmonic generation (SHG) by a multi-resonant nanostructure. A 100 GaAs layer embedded in metal-insulator-metal waveguide is shown support localized resonances. One resonance enhances the polarization due transverse magnetic (TM)-polarized pump wavelength near 3.2 µ m , while another set TE-polarized generated ( 1.6 ). The measured SHG efficiency higher than 10 ? 9 mathvariant="normal">W 1 ranging from 2.9 3.3 which agrees with theoretical computations. This typically 4 orders of magnitude equivalent membrane.