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.

Nonlinear Anisotropic Dielectric Metasurfaces for Ultrafast Nanophotonics

Della Valle, Giuseppe;Ganzer, Lucia;Stoll, Tatjana;Longhi, Stefano;Cerullo, Giulio
2017-01-01

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.
all-optical modulation; dielectric metasurfaces; Mie resonances; Nonlinear optics; ultrafast spectroscopy; Atomic and Molecular Physics, and Optics;
File in questo prodotto:
File Dimensione Formato  
Manuscript_rev.pdf

Open Access dal 15/08/2018

: Post-Print (DRAFT o Author’s Accepted Manuscript-AAM)
Dimensione 8.63 MB
Formato Adobe PDF
8.63 MB Adobe PDF Visualizza/Apri
Selezione_1_Della_Valle_ACSP_2017.pdf

Accesso riservato

Descrizione: Articolo principale
: Publisher’s version
Dimensione 4.62 MB
Formato Adobe PDF
4.62 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/1039654
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 52
  • ???jsp.display-item.citation.isi??? 48
social impact