Abstract

Wavelength-selective metamaterial absorbers in the mid-infrared range are demonstrated by using multiple tungsten cross resonators. By adjusting the geometrical parameters of cross resonators in single-sized unit cells, near-perfect absorption with single absorption peak tunable from 3.5 µm to 5.5 µm is realized. The combination of two, three, or four cross resonators of different sizes in one unit cell enables broadband near-perfect absorption at mid-infrared range. The obtained absorption spectra exhibit omnidirectionality and weak dependence on incident polarization. The underlying mechanism of near-perfect absorption with cross resonators is further explained by the optical mode analysis, dispersion relation and equivalent RLC circuit model. Moreover, thermal analysis is performed to study the heat generation and temperature increase in the cross resonator absorbers, while the energy conversion efficiency is calculated for the thermophotovoltaic system made of the cross resonator thermal emitters and low-bandgap semiconductors.

Department(s)

Mechanical and Aerospace Engineering

Comments

National Science Foundation (NSF) (ECCS-1653032, DMR-1552871); Office of Naval Research (ONR) (N00014-16-1-2408); U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357).

Keywords and Phrases

Conversion efficiency; Energy conversion; Geometry; Infrared devices; Metamaterials; Resonant circuits; Thermoanalysis; Tungsten; Dispersion relations; Incident polarization; Metamaterial absorbers; Mid-infrared range; Omnidirectionality; Temperature increase; Thermophotovoltaic systems; Wavelength-selective; Resonators

International Standard Serial Number (ISSN)

1094-4087

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2018 Optical Society of America (OSA), All rights reserved.

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