Nonlinear Anisotropic Dielectric Metasurfaces for Ultrafast Nanophotonics

Giuseppe Della Valle*, Ben Hopkins, Lucia Ganzer, Tatjana Stoll, Mohsen Rahmani, Stefano Longhi, Yuri S. Kivshar, Costantino De Angelis, Dragomir N. Neshev, Giulio Cerullo

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    74 Citations (Scopus)

    Abstract

    We report on the broadband transient optical response of anisotropic, amorphous silicon nanobricks that exhibit Mie-type resonances. A quantitative model is developed to identify and disentangle the three physical processes that govern the ultrafast changes of the nanobrick optical properties, namely, two-photon absorption, free-carrier relaxation, and lattice heating. We reveal a set of operating windows where ultrafast all-optical modulation of transmission is achieved with full return to zero in 20 ps. This is made possible because of the distinct dispersive features exhibited by the competing nonlinear processes in transmission and despite the slow (nanosecond) internal lattice dynamics. The observed ultrafast switching behavior can be independently engineered for both orthogonal polarizations using the large anisotropy of nanobricks, thus allowing ultrafast anisotropy control. Our results categorically ascertain the potential of all-dielectric resonant nanophotonics as a platform for ultrafast optical devices and reveal the possibility for ultrafast polarization-multiplexed displays and polarization rotators.

    Original languageEnglish
    Pages (from-to)2129-2136
    Number of pages8
    JournalACS Photonics
    Volume4
    Issue number9
    DOIs
    Publication statusPublished - 20 Sept 2017

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