On the use of membrane metasurfaces for high-efficiency third harmonic generation

Metasurfaces are used for various applications from beam shaping and focusing to enhancing nonlinear effects and quantum optics. Here, we present our efforts to use metasurfaces to enhance third harmonic generation (THG) in the ultraviolet (UV) range. Initial simulations show that a metasurface patterned on a silicon nitride membrane can increase efficiency by a couple of orders of magnitude when compared to a non-patterned membrane of the same thickness. Further simulation and fabrication efforts pinpoint the conditions for such enhancement to take place as well as the influence of the fabrication uncertainties on the THG efficiency and wavelength.