Efficient terahertz anti-reflection properties of metallic anti-dot structures

Neeraj, Kumar ; Choudhury, Samiran ; Polley, Debanjan ; Acharya, Rakhi ; Sinha, Jaivardhan ; Barman, Anjan ; Mitra, Rajib Kumar (2017) Efficient terahertz anti-reflection properties of metallic anti-dot structures Optics Letters, 42 (9). p. 1764. ISSN 0146-9592

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Official URL: http://doi.org/10.1364/OL.42.001764

Related URL: http://dx.doi.org/10.1364/OL.42.001764

Abstract

We report the use of micrometer-sized copper (Cu) anti-dot structures as a novel terahertz (THz) anti-reflection coating (ARC) material and their superior performance over conventionally used metallic (Cu) thin films. Cu anti-dot structures of two different thicknesses (7 and 10 nm) with varying anti-dot diameters (100, 200, and 300 μm, inter-anti-dot separation fixed at 100 μm) are deposited on silicon substrates by RF magnetron sputtering and e-beam evaporation. The anti-reflection performance of these samples is studied in the frequency range of 0.3-2.2 THz. While continuous metallic (Cu) thin film minimizes the Fabry-Perot (FP) peak, it also suppresses the primary transmission peak, reducing the advantage due to the former effect. On the contrary, the anti-dot arrays reduce both the absolute amplitude of the FP peak and the amplitude ratio (AR) of the FP peak to the primary peak, making them a superior material for ARC applications. The AR can be further manipulated by varying the anti-dot size. A universal conductivity phase-matching condition, which is a prerequisite for the disappearance of the FP peak, is observed in these samples. The enhanced anti-reflection performance promotes these anti-dot structures as an efficient terahertz ARC material.

Item Type:Article
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ID Code:116203
Deposited On:07 Apr 2021 10:36
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