Opto-thermally controlled beam steering in nonlinear all-dielectric metastructures
Authors: Rocco D.; Gandolfi M.; Tognazzi A.; Pashina O.; Zograf G.; Frizyuk K.; Gigli C.; Leo G.; Makarov S.; Petrov M.; De Angelis C.
Autors Affiliation: Department of Information Engineering, University of Brescia, via Branze 38, Brescia, 25123,Italy; CNR-INO (National Institute of Optics), via Branze 45, Brescia, 25123, Italy; ITMO University, Department of Physics and Engineering, St. Petersburg Russian Federation; Matyriaux et Phynomies Quantiques, University de Paris, CNRS, Paris, 75013, France
Abstract: Reconfigurable metasurfaces have recently gained a lot of attention in applications such as adaptive meta-lenses, hyperspectral imaging and optical modulation. This kind of metastructure can be obtained by an external control signal, enabling us to dynamically manipulate the electromagnetic radiation. Here, we theoretically propose an AlGaAs device to control the second harmonic generation (SHG) emission at nanoscale upon optimized optical heating. The asymmetric shape of the used meta-atom is selected to guarantee a predominant second harmonic (SH) emission towards the normal direction. The proposed structure is concurrently excited by a pump beam at a fundamental wavelength of 1540 nm and by a continuous wave (CW) control signal above the semiconductor band gap. The optical tuning is achieved by a selective optimization of meta-atoms SH phase, which is modulated by the control signal intensity. We numerically demonstrate that the heating induced in the meta-atoms by the CW pump can be used to dynamically tune the device properties. In particular, we theoretically demonstrate a SH beam steering of 8? with respect to the vertical axis for an optimized device with average temperature increase even below 90 degrees C.
Journal/Review: OPTICS EXPRESS
Volume: 29 (23) Pages from: 26 to: 28
More Information: Agence Nationale de la Recherche (ANR-18-CE92-0043, NANOPAIR); European Commission (899673, FETOPEN-01-2018-2019-2020); Consiglio Nazionale delle Ricerche (Joint Laboratories program, SAC.AD002.026); Ministero dell´Istruzione, dell´Universita e della Ricerca (2017MP7F8F, PRIN NOMEN); Russian Foundation for Basic Research (20-32-90238); Grant of the President of the Russian Federation (2360.2020.2).KeyWords: 2nd-harmonic generation; visible- light; metasurface; nanoantennas; gaas; nanoparticles; optics; lenses; indexDOI: 10.1364/OE.440564