Nonlinear mirror with all-dielectric metasurface

Summary form only given. A nonlinear mirror based on the nonlinear optical frequency conversion has been established as a universal tool for ultrafast control of laser dynamics [1]. However, traditional approaches are based on bulk crystals posing major difficulties on phase matching and alignment. Ultra-thin nonlinear mirrors based on all-dielectric metasurfaces would offer a major breakthrough to develop this concept [2-4]. The high refractive index and strong cubic optical nonlinearity of Silicon offer the opportunity to design the metasurface using Si nanoparticles for tailoring the directionality of nonlinear emission at the nanoscale [5-7]. Here, we study theoretically a nonlinear mirror based on the third-harmonic generation (THG) in the silicon nanodisks metasurfaces. By flexible control on the scattering process of light in such nanostructured metasurface, we are able to achieve nearly 100% reflection for the fundamental wave and more than 97% forward emission for the third harmonic (TH) radiation. Nonlinear mirrors based on the harmonic generation can be generally divided into two classes: (i) one class, when the fundamental wave is fully transmitted while the harmonic output is emitted only backwards; and (ii) when the fundamental wave is fully reflected from the metasurface while the harmonic output is emitted only in the forward directions, see Figs. 1(a,b)