Browsing by Author "Chi, Nai-Chen"

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High Transmittance and Broaden Bandwidth through the Morphology of Anti-Reflective Layers on THz Polarizer with Si Substrate
(2017-01-01)
Chi, Nai-Chen
;
Yu, Ting-Yang
;
Tsai, Hsin-Cheng
;
Wang, Shiang-Yu
;
Luo, Chih-Wei
To improve the transmittance of THz component and overcome the difficulties of fragile structure as well as ensuring precise alignment of existing methods, a new method involving the mature 3DIC through-silicon via (TSV) technology has been proposed to make anti-reflection layer with suitable effective refractive index based on the robustness of Si wafer. Cu wire-grid polarizers were also fabricated on wafer. The THz polarizers were completed after wafer bonding with Cu sealing ring and In/Sn guard ring. Not only the new method is easier for production with better performance, but also the silicon substrate has several advantages. The novel method has proven that THz optical component could be constructed with a nearly 100% transmittance, or widened the transmittance spectrum range from 0.5 to 2 THz when transmittances is sacrificed to 70% instead of a near 100%. Furthermore, a robust structure could also be expected with broadband transmission and excellent extinction ratio. It is properly optimized for mass production because the fabrication method could be easily done and does not required high cost.
High Transmittance Broadband THz Polarizer Using 3D-IC Technologies
(2017-01-01)
Chi, Nai-Chen
;
Yu, Ting-Yang
;
Tsai, Hsin-Cheng
;
Wang, Shiang-Yu
;
Luo, Chih-Wei
A novel method of fabricating high transmittance and broadband terahertz (THz) polarizers is introduced with several advantages. A polarizer with an approximate 100% transmittance is demonstrated with single central frequency of anti-reflection (AR) layers between 0.5 THz and 2 THz. Broadband polarizer, which has a transmission spectrum of over 70% uniformity, is fabricated by bonding two wafers with different AR layers. The bandwidth of broadband THz polarizer exceeds 1 THz. Extinction ratio of the polarizer is about 30 dB depending on the frequency and Cu wire pitch. The high transmittance and broadband THz polarizer can be achieved through deep reactive-ion etching (DRIE) and wafer bonding. This new fabricating method of THz polarizers has advantages of lower cost, no accurate alignment requirement and robust structure. Therefore, this approach can possibly benefit the mass production of THz optical components in THz applications and even more.
Robust terahertz polarizers with high transmittance at selected frequencies through Si wafer bonding technologies
(2017-12-01)
Yu, Ting-Yang
;
Chi, Nai-Chen
;
Tsai, Hsin-Cheng
;
Wang, Shiang-Yu
;
Luo, Chih-Wei
Terahertz (THz) polarizers with robust structure and high transmittance are demonstrated using 3D-integrated circuit (IC) technologies. A Cu wire-grid polarizer is sealed and well protected by Si-bonded wafers through a low-temperature eutectic bonding method. Deep reactive-ion etching is used to fabricate the anti-reflection (AR) layers on outward surfaces of bonded wafers. The extinction ratio and transmittance of polarizers are between 20 dB and 33 dB, and 13 dB and 27 dB for 10 mu m and 20 mu m pitch wire-grids, respectively, and 100% at central frequency, depending on frequency and AR layer thickness. The process of polarizer fabrication is simple from mature semiconductor manufacturing techniques that lead to high yield, low cost, and potential for THz applications. (C) 2017 Optical Society of America