標題: High Transmittance Silicon Terahertz Polarizer Using Wafer Bonding Technology
作者: Yu, Ting-Yang
Tsai, Hsin-Cheng
Wang, Shiang-Yu
Luo, Chih-Wei
Chen, Kuan-Neng
電子物理學系
電子工程學系及電子研究所
Department of Electrophysics
Department of Electronics Engineering and Institute of Electronics
關鍵字: wire grid polarizer;terahertz wave;anti-reflection;wafer bonding;eutectic point;DRIE
公開日期: 1-Jan-2015
摘要: Due to the difficulties faced in fabricating robust Terahertz (THz) optical components with low Fresnel reflection loss, the need to increase the efficiency of THz system with reduced cost is still considered as one of the most essential tasks. In this report, a new low cost THz polarizer with robust structure is proposed and demonstrated. This new THz wire grid polarizer was based on an anti-reflection (AR) layer fabricated with low temperature metal bonding and deep reactive-ion etching (DRIE). After patterning Cu wire gratings and the corresponding In/Sn solder ring on the individual silicon wafers, the inner gratings were sealed by wafer-level Cu to In/Sn guard ring bonding, providing the protection against humidity oxidation and corrosion. With the low eutectic melting point of In/Sn solder, wafers could be bonded face to face below 150 degrees C. Two anti-reflection layers on both outward surfaces were fabricated by DRIE. With the mixing of empty holes and silicon, the effective refractive index was designed to be the square root of the silicon refractive index. The central frequency of the anti-reflection layers was designed between 0.5THz to 2THz with an approximate bandwidth of 0.5THz. The samples were measured with a commercial free-standing wire grid polarizer by a THz time domain spectroscopy (THz-TDS) from 0.2THz to 2.2THz. The power transmittance is close to 100% at central frequency. Extinction ratio of the polarizer is between 20dB to 40dB depending on the frequency. The advantages of this new polarizer include high transmittance, robust structure andlow cost with no precision optical alignment required.
URI: http://dx.doi.org/10.1117/12.2187435
http://hdl.handle.net/11536/129754
ISBN: 978-1-62841-751-7
ISSN: 0277-786X
DOI: 10.1117/12.2187435
期刊: TERAHERTZ EMITTERS, RECEIVERS, AND APPLICATIONS VI
Volume: 9585
起始頁: 0
結束頁: 0
Appears in Collections:Conferences Paper


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