Multi-spectral materials: hybridisation of optical plasmonic filters, a mid infrared metamaterial absorber and a terahertz metamaterial absorber.

James Grant,David R S Cumming,Iain J H Mccrindle

doi:10.1364/oe.24.003451

James Grant, David R S Cumming + Show 1 more

Open Access

https://doi.org/10.1364/oe.24.003451

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Abstract

Multi-spectral imaging systems typically require the cumbersome integration of disparate filtering materials and detectors in order to operate simultaneously in multiple spectral regions. Each distinct waveband must be detected at different spatial locations on a single chip or by separate chips optimised for each band. Here, we report on a single component that optically multiplexes visible, Mid Infrared (4.5 μm) and Terahertz (126 μm) radiation thereby maximising the spectral information density. We hybridise plasmonic and metamaterial structures to form a device capable of simultaneously filtering 15 visible wavelengths and absorbing Mid Infrared and Terahertz. Our synthetic multi-spectral component could be integrated with silicon complementary metal-oxide semiconductor technology where Si photodiodes are available to detect the visible radiation and micro-bolometers available to detect the Infrared/Terahertz and render an inexpensive, mass-producible camera capable of forming coaxial visible, Infrared and Terahertz images.

Highlights

Multi-spectral imaging using visible, Infrared (IR) and Terahertz (THz) radiation is a burgeoning topic in the field of remote sensing
This peak is present in the spectral characteristics of the fabricated standalone THz MM absorber indicating that its origin is directly related to the addition of the 4 μm SiO2 and the THz electric ring resonator (ERR) layers
In this article we have demonstrated the design, fabrication and characterisation of a new type of Synthetic multi-spectral materials (SMMs) that hybridises optical plasmonic filters with a mid IR (MIR) MM absorber and a THz MM absorber to combine multiple functionalities as well as multi-spectral capabilities into a single material

Summary

Introduction

Multi-spectral imaging using visible, Infrared (IR) and Terahertz (THz) radiation is a burgeoning topic in the field of remote sensing. Synthetic multi-spectral materials (SMMs): structured materials capable of operating over different wavebands simultaneously, offer a way to coaxially filter and absorb visible, IR and THz radiation and offer an attractive alternative to conventional detection methods [6,7,8,9,10]. In this paper we demonstrate through simulations and experimentally a SMM capable of filtering 15 visible wavelengths and one NIR wavelength while absorbing MIR and THz radiation Such a device could be integrated with a Si CMOS chip where the visible detection would be done by Si photodiodes and the IR/THz detection done by microbolometer sensors positioned above the integrated circuit and render a component capable of forming coaxial visible, IR and THz images. MM based FPAs have been developed in both the S band (2-4 GHz) [27] and at THz frequencies (2.5 THz) where the MM absorbers were monolithically integrated into a standard 0.35 μm CMOS process and the vanadium oxide microbolometer sensors deposited on top [30, 31]

Device design and simulation

Fabrication and device characterisation

Results

Conclusion