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Field-effect modulation of the local density of optical states in a reflectarray metasurface

Kafaie Shirmanesh, Ghazaleh and Sokhoyan, Ruzan and Han, Seunghoon and Atwater, Harry A. (2016) Field-effect modulation of the local density of optical states in a reflectarray metasurface. In: Active Photonic Materials VIII. Proceedings of SPIE. No.9920. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 992018. ISBN 9781510602311.

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During recent years, advances in the design of arrays of subwavelength optical elements with special electromagnetic properties have enabled quasi two-dimensional structures that control and manipulate electromagnetic phase, amplitude and polarization. Active control of the response of metasurfaces is possible using transparent conducting oxides such as Indium Tin Oxide (ITO) as a tunable active material [1]. Changing the complex permittivity of ITO by applying a voltage yields modulation of reflected wave phase and amplitude. To achieve this, we designed subwavelength antenna arrays consisting of a gold back reflector and gold fishbone antennas. Planar dielectric layers containing a gate tunable layer of ITO are sandwiched between the back reflector and the antenna. The obtained structure shows resonance around 1.5 µm. As a result, based on the 1.54 µm photoluminescence emission of Er doped Al_2O_3 films, we embedded trivalent erbium ions as quantum emitters inside an alumina host within the metasurface in order to enhance the local density of optical states (LDOS). Simulations indicate the designed structure shows a significant LDOS enhancement (of order of hundreds). By applying a bias between the antenna and the ITO layer, across an HfO_2 gate dielectric, we can control the permittivity of ITO and hence dynamically modulate the decay rate of quantum emitters embedded within the structure. In this way, we can achieve LDOS enhancement modulation of about 325%.

Item Type:Book Section
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URLURL TypeDescription
Kafaie Shirmanesh, Ghazaleh0000-0003-1666-3215
Sokhoyan, Ruzan0000-0003-4599-6350
Atwater, Harry A.0000-0001-9435-0201
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).
Series Name:Proceedings of SPIE
Issue or Number:9920
Record Number:CaltechAUTHORS:20180706-085245122
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Official Citation:Ghazaleh Kafaie Shirmanesh, Ruzan Sokhoyan, Seunghoon Han, Harry A. Atwater, "Field-effect modulation of the local density of optical states in a reflectarray metasurface (Conference Presentation)", Proc. SPIE 9920, Active Photonic Materials VIII, 992018 (9 November 2016); doi: 10.1117/12.2238835;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87581
Deposited By: George Porter
Deposited On:06 Jul 2018 16:11
Last Modified:15 Nov 2021 20:49

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