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.
© 2017 Optical Society of America
Full Article | PDF ArticleMore Like This
Ting-Yang Yu, Nai-Chen Chi, Hsin-Cheng Tsai, Shiang-Yu Wang, Chih-Wei Luo, and Kuan-Neng Chen
Opt. Lett. 42(23) 4917-4920 (2017)
Yiwen Sun, Shengxin Yang, Pengju Du, Fei Yan, Junle Qu, Zexuan Zhu, Jian Zuo, and Cunlin Zhang
Opt. Express 25(3) 1723-1731 (2017)
Manjakavahoaka Razanoelina, Shohei Ohashi, Iwao Kawayama, Hironaru Murakami, Annick F. Dégardin, Alain J. Kreisler, and Masayoshi Tonouchi
Opt. Lett. 42(15) 3056-3059 (2017)