Enhanced nonlinear optical response by strong coupling between plasmonic antenna arrays and epsilon-near-zero film

Abstract

Abstract A coupled structure of center-symmetric orthogonal nano-antenna arrays on fluorine-doped tin oxide (FTO) is designed to enhance the nonlinear response by the strong coupling. Further, we study the roles of structural and material parameters in determining the linear and nonlinear optical response of antenna-FTO metasurface. This structure shows broadband spectrum (∼900 nm) and large nonlinearity with nonlinear refractive index n 2 of 1.02 cm2/GW, which is about 400 times higher than that of bare FTO film. The results provide a promising platform for the realization of ultracompact and large nonlinear optical devices.