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Published March 2019 | Supplemental Material + Published
Journal Article Open

Tunable all-dielectric metasurface for phase modulation of the reflected and transmitted light via permittivity tuning of indium tin oxide


We propose an electrically tunable metasurface, which can achieve relatively large phase modulation in both reflection and transmission modes (dual-mode operation). By integration of an ultrathin layer of indium tin oxide (ITO) as an electro-optically tunable material into a semiconductor-insulator-semiconductor (SIS) unit cell, we report an approach for active tuning of all-dielectric metasurfaces. The proposed controllable dual-mode metasurface includes an array of silicon (Si) nanodisks connected together via Si nanobars. These are placed on top of alumina and ITO layers, followed by a Si slab and a silica substrate. The required optical resonances are separately excited by Si nanobars in reflection and Si nanodisks in transmission, enabling highly confined electromagnetic fields at the ITO-alumina interface. Modulation of charge carrier concentration and refractive index in the ITO accumulation layer by varying the applied bias voltage leads to 240° of phase agility at an operating wavelength of 1696 nm for the reflected transverse electric (TE)-polarized beam and 270° of phase shift at 1563 nm for the transmitted transverse magnetic (TM)-polarized light. Independent and isolated control of the reflection and transmission modes enables distinctly different functions to be achieved for each operation mode. A rigorous coupled electrical and optical model is employed to characterize the carrier distributions in ITO and Si under applied bias and to accurately assess the voltage-dependent effects of inhomogeneous carrier profiles on the optical behavior of a unit cell.

Additional Information

© 2019 Hossein Mosallaei et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 Public License. Received October 18, 2018; revised December 20, 2018; accepted December 24, 2018. Published Online: 2019-01-25. A. F., M. M. S., and H. M. would like to acknowledge financial support by the U.S. Air Force Office of Scientific Research (AFOSR), #FA9550-14-1-0349, Funder Id: http://dx.doi.org/10.13039/100000181 and #FA9550-18-1-0354, Funder Id: http://dx.doi.org/10.13039/100000181. G. K. S., R. S., and H. A. A. would like to acknowledge the funding by the U.S. Air Force Office of Scientific Research (AFOSR), #FA9550-16-1-0019, Funder Id: http://dx.doi.org/10.13039/100000181. The authors gratefully acknowledge useful discussions with Phillip Jahelka from the California Institute of Technology.

Attached Files

Published - _Nanophotonics__Tunable_all-dielectric_metasurface_for_phase_modulation_of_the_reflected_and_transmitted_light_via_permittivity_tuning_of_indium_tin_oxide.pdf

Supplemental Material - nanoph-2018-0176_suppl.doc



Additional details

August 22, 2023
October 20, 2023