Nonlinear Fano-Resonant Dielectric Metasurfaces

作者：Yang, Yuanmu; Wang, Wenyi; Boule**aa, Abdelaziz; Kravchenko, Ivan I.; Briggs, Dayrl P.; Puretzky, Alexander; Geohegan, David; Valentine, Jason^*

来源：Nano Letters, 2015, 15(11): 7388-7393.

DOI：10.1021/acs.nanolett.5b02802

• Metamaterial
• dielectric antenna
• Fano resonance
• third harmonic generation

Strong nonlinear light-matter interaction is highly sought-after for a variety of applications including lasing and all-optical light modulation. Recently, resonant plasmonic structures have been considered promising candidates for enhancing nonlinear optical processes due to their ability to greatly enhance the optical near-field; however, their small mode volumes prevent the inherently large nonlinear susceptibility of the metal from being efficiently exploited. Here, we present an alternative approach that utilizes a Fano-resonant silicon metasurface. The metasurface results in strong near-field enhancement within the volume of the silicon resonator while minimizing two photon absorption. We measure a third harmonic generation enhancement factor of 1.5 x 10(5) with respect to an unpattemed silicon film and an absolute conversion efficiency of 1.2 x 10(-6) with a peak pump intensity of 3.2 GW cm(-2). The enhanced nonlinearity, combined with a sharp linear transmittance spectrum, results in transmission modulation with a modulation depth of 36%. The modulation mechanism is studied by pump-probe experiments.

• 出版日期2015-11