Nonlinear Gallium Phosphide Nanostructures for Frequency Conversion and All-Optical Switching

G. GRINBLAT; G. Q. MORETTI; H. ZHANG; M. P. NIELSEN; L. KRIVITSKY; R. BERTÉ; Y. LI; B. TILMANN; E. CORTÉS; A. TITTL; R. F. OULTON; A. I. KUZNETSOV; S. A. MAIER; A. V. BRAGAS

Congreso; The 16th International Congress on Artificial Materials for Novel Wave Phenomena; 2022

Sub-wavelength dielectric resonators can be designed to highly confine the incoming light fields in their interior, strongly amplifying intrinsic nonlinear responses. In this work, we propose the use of Gallium Phosphide (GaP) nanostructures with high-Q and low-Q factor resonances for efficient frequency conversion and sub-100 fs all-optical switching, respectively. We report theoretical estimations of second harmonic generation efficiency as high as >0.1% in metasurfaces supporting quasi-bound states in the continuum, as well as experimental ultrafast differential reflectivity values close to 40% in anapole-resonant single nanoantennas. The results of this investigation demonstrate the potential of GaP nanostructures for nonlinear nanophotonics.