Giant photoinduced reflectivity modulation of nonlocal resonances in silicon metasurfaces

Year: 2023

Authors: Tognazzi A., Franceschini P., Sergaeva O., Carletti L., Alessandri I., Finco G., Takayama O., Malureanu R., Lavrinenko AV., Cino AC., De Ceglia D., De Angelis C.

Autors Affiliation: Univ Palermo, Dept Engn, Palermo, Italy; Natl Inst Opt, Natl Res Council, Brescia, Italy; Univ Brescia, Dept Informat Engn, Brescia, Italy; ITMO Univ, Sch Phys & Engn, St Petersburg, Russia; Swiss Fed Inst Technol, Inst Quantum Elect, Dept Phys, Opt Nanomat Grp, Zurich, Switzerland; Tech Univ Denmark, Dept Elect & Photon Engn, Kongens Lyngby, Denmark.

Abstract: Metasurfaces offer a unique playground to tailor the electromagnetic field at subwavelength scale to control polarization, wavefront, and nonlinear processes. Tunability of the optical response of these structures is challenging due to the nanoscale size of their constitutive elements. A long-sought solution to achieve tunability at the nanoscale is all-optical modulation by exploiting the ultrafast nonlinear response of materials. However, the nonlinear response of materials is inherently very weak, and, therefore, requires optical excitations with large values of fluence. We show that by properly tuning the equilibrium optical response of a nonlocal metasurface, it is possible to achieve sizable variation of the photoinduced out-of-equilibrium optical response on the picosecond timescale employing fluences smaller than 250 mu J / cm(2), which is 1 order of magnitude lower than previous studies with comparable reflectivity variations in silicon platforms. Our results pave the way to fast devices with large modulation amplitude.

Journal/Review: ADVANCED PHOTONICS

Volume: 5 (6)      Pages from:   to:

More Information: C. De Angelis and O. Se rgaeva would like to acknowledge the support of the Russian Science Foundation (Grant No. 22-12-00204). C. De Angelis also would like to acknowledge the financial support from the European Community through the METAFAST Project (H2020-FETOPEN-2018-2020, Grant No. 899673) and the Ministero Italiano dell’Istruzione (MIUR) through the METEOR Project (No. PRIN-2020, 2020EYLJT_002). A. Tognazzi thanks the European Union for the financial support through FESR o FSE, PON Ricerca e Innovazione 2014-2020-DM 1062/2021 and the University of Palermo through Fondo Finalizzato alla Ricerca di Ateneo 2023. A. C. Cino acknowledges financial support from the European Union, NextgenerationEU, MUR D.M 737/2021, through the Project Eurostart22 (No. PRJ-0988).
KeyWords: nonlocal metasurface; nanophotonics; ultrafast modulation; Fano resonance
DOI: 10.1117/1.AP.5.6.066006

Citations: 6
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