Quenching of second-harmonic generation by epsilon-near-zero media

Abstract

Epsilon-near-zero (ENZ) media were demonstrated to exhibit unprecedented strong nonlinear optical properties including giant second-harmonic generation (SHG) due to their field-enhancement effect. Here, on the contrary, we report the quenching of SHG by the ENZ media. We find that when a tiny nonlinear particle is placed very close to a subwavelength ENZ particle, the SHG from the nonlinear particle can be greatly suppressed. The SHG quenching effect originates from the extraordinary prohibition of electric fields occurring near the ENZ particle due to evanescent scattering waves, which is found to be universal in both isotropic and anisotropic ENZ particles, irrespective of their shapes. Based on this principle, we propose a kind of dynamically controllable optical metasurface exhibiting switchable SHG quenching effect. Our work enriches the understanding of optical nonlinearity with ENZ media and could find applications in optical switches and modulators.