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標題: | 垂直配向高分子穩定型液晶應用於快速響應光開關與可調波長濾波器 Fast Response Optical Switch and Wavelength Tunable Filter using Vertically-Aligned Polymer Stabilized Liquid Crystals |
作者: | Hong-Yu Lai 賴泓宇 |
指導教授: | 蔡永傑 |
關鍵字: | Fabry- Perot共振腔,布拉格反射鏡,高分子穩定型液晶,液晶,可調變波長濾波器,高分子穩定配向,聚合電壓,可調式光開關, Fabry- Perot cavity,Distributed Bragg reflectors,Polymer stabilized liquid crystal (PSLC),Liquid Crystal,Wavelength tunable filter,polymer sustained alignment,curing voltage,Tunable optical switch, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 液晶技術的應用已被廣泛應用在各方面,並不在限於顯示器,像是智慧窗戶、光學門閥和可調波長濾波器,還有很多方面可應用。本研究的主要目的是利用高分子穩定型液晶有較快之反應時間,製作快速響應可調頻濾波器/光開關,可調頻元件是將液晶注入於由兩片有布拉格反射鏡結構的ITO玻璃所組成之Fabry-Pérot共振腔。內容分為三個部分作探討,第一部分,我們先將PSLC製作於一般型的液晶盒,並對各種可調參數作探討,例如不同單體材料、不同單體濃度和不同聚合電壓大小,分析各個數據的優劣,並找出最適合應用於可調式光開關與可調波長液晶濾波器的參數。
第2部分,我們發現加入聚合電壓可以有效地降低高分子液晶本身的散射效應,使得PSLC濾波器元件在外加電壓時可以保持高穿透率並調變波長,最後並探討聚合電壓大小對元件的可調變調範圍與半高寬值(FWHM)之影響。 第3部分,利用外加電壓改變腔內折射率,使共振波長位移,達到開關的特性,我們使用633nm的雷射量測元件的開關特性,在光開關的特性表現上,除了低於2ms的響應時間外,跟一般散射型的PSLC樣品相比,有較低的電壓,且有較佳的對比。 Liquid crystal technologies have been used in our daily life. It has not only been utilized in displays but also in other applications such as optical shutters for optical instruments, Smart Window or wavelength tunable filter. In this study, we take the advantage of fast response time of VA-PSLC and place it in Fabry- Pérot cavity to develop a fast response tunable optical switch and wavelength tunable filter. The polymer stabilized liquid crystal tunable filters was fabricated by the combination distributed Bragg reflectors with an intra-cavity liquid crystal material. It is separated into three parts. The first part of the thesis will introduce the fundamental optical properties of polymer stabilized liquid crystals in normal cell. We studied the characteristics of PSLC and the influence of parameters such as different polymer monomer, polymer concentration and curing voltage on PSLC. By comparing with the result of different parameters, we can obtain the most suitable parameter for fabricating tunable optical switch and wavelength tunable filter. In the second part, we find the method of “curing voltage” to be able to help reduce the strong scattering effect of the VA-PSLC (Vertical Alignment PSLC) significantly. Therefore, the PSLC wavelength tunable filter can have high transmittance to modulate the resonance wavelength after applying voltage. We also discuss the influence of the magnitude of curing voltage on FWHM(Full width at half maximum) and tunable range. We study the effect of PSLC wavelength tunable filter. In the third part, we utilize the effect of the resonance wavelength shift of Fabry- Pérot device by applying voltage thus develop an externally controlled/tunable optical switch. We measure the electro-optical characteristic of tunable optical switch by applying laser light source (633nm). The performance characteristics of tunable optical switch are fast response time of less than 2 milliseconds, low operation voltage and improved contrast ratio. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/21029 |
DOI: | 10.6342/NTU201700249 |
全文授權: | 未授權 |
顯示於系所單位: | 光電工程學研究所 |
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