生醫檢測用旋轉分析板雙偏極光波導干涉儀之設計與研製

Abstract

波導干涉術(Waveguide Interferometry)是指在波導內全反射傳遞的光，會因波導邊界之折射率或厚度不同造成相位的變化，配合干涉術產生干涉條紋，並利用相移法求出干涉條紋的相位值的一種光學檢測技術。由於此檢測技術可以TE和TM兩種偏極光進行量測，故能提供較多資訊推導出波導上樣本的折射率與厚度等參數值，故可應用於生物分子反應檢測上。本論文提出一具有雙偏極光量測的波導干涉儀架構，以馬赫-曾德干涉術(Mach-Zehnder Interferometry)光路架構為基礎，其中包含自行設計製作的波導晶片、可切換偏極態的樣本光路和參考光路、四分之ㄧ波板和分析板進行相位調制，並使用CCD、IMAQ1409影像擷取卡、LabVIEW程式完成訊號擷取與分析，另外加入溫度控制模組於系統中，可有效降低環境溫度擾動對干涉訊號漂移的誤差。 本研究主要目的是為了解決表面電漿共振術和橢偏術應用於生醫檢測領域所面臨的困難，表面電漿共振術由於檢測原理的限制只能使用TM偏極態量測，所得資訊較無法直接進行複雜的生物反應研究分析；而橢偏術因入射光正向打入樣本時須在水溶液內全反射，會有折射現象造成判讀角度上的困難。雙偏極光之波導干涉術一方面因同時使用TE和TM偏極態可得到較多訊號進行生物參數反解，另一方面由於入射光在波導內傳遞，不會有入射介質折射率改變的問題，同時解決上述兩種檢測技術遭遇的困難。此外由於波導干涉術入射光在波導內多次全反射其訊號為疊加，和上述兩種技術僅為單點量測方式相比具有較高的解析度。 目前所架設雙偏極光之波導干涉儀已完成相關的生物反應檢測驗證。在ELISA生化反應和重現性實驗，成功的量測出Anti-IgG與不同濃度的IgG反應結果，所得訊號將可提供生物醫學領域人員進行複雜生化反應的分析研究。為增進系統的精確度和應用面，已就光機架構、訊號偵測、波導晶片、流道系統等方面做更進一步的研究，使本論文研發之創新生醫檢測技術－雙偏極光波導干涉儀功能更為完備。

When light beam propagates in the waveguide, the optical phase is influenced by the boundary index and thickness variations. Applying the phase modulation method in the configuration, the optical phase can be retrieved from the interference fringes. This technique combining the waveguide and the interferometry is so called “waveguide interfermetry”. It offers more information to resolve bio-sample parameters because both TE and TM polarizations are available. Therefore, it is very suitable to being applied to bio-molecules interactions measurement. In this thesis, a newly developed dual-polarization waveguide interferometry system is developed. The Mach-Zehnder Interferometry based optical configuration includes the newly developed waveguide chip, the sample and the reference light beams equipped with different polarizations, the phase modulation mechanism by combining quarter wave plate and analyzer, CCD, IMAQ card, and LabVIEW program to acquire the signal. Moreover, integrating the analog temperature control system in this optical biochip system further reduces the influence of the environmental disturbance. The motivation of this dissertation is to solve some problems faced by SPR and ellipsometry detection techniques in bio-tech analysis. Due to generic optical configuration limitations, SPR technique can only adopt TM polarization detection and thus may have less information to retrieve parameters needed to explore the complex bio-reactions. In ellipsometry detection, the incident light path through the bio-sample layer changes due to the bio-sample index variations, which makes it hard to determine the exact incident angle needed for inverse calculations. In order to improve shortcomings of these techniques, the dual-polarization waveguide interferometry system is developed and built during the course of this research. The incident light beam in this method can sense the bio-sample by using both TE and TM polarizations and is propagated in the waveguide without suffering variable indices when light beam penetrates across bio-sample and chip layers. Furthermore, the resolution of waveguide interferomerty is increased due to the multi-reflections exist the waveguide. The dual-polarized waveguide interferometry system has bee proved the ability to detect the bio-molecules interactions. Some ELISA interaction and regeneration experiments were completed. The Anti-IgG and IgG reaction was successfully measured. These experimental results can be converted into the complex bio-reaction information sought after by biomedical researchers. To further improve the resolution and to expand the application regime of this system, several work items were proposed, which include minimizing the optical system size, simplifying the signal detection part, reducing the waveguide chip cost, and integrating the flow injection system. With these suggested potential improvements implemented, the dual-polarization waveguide interferometry system is expected to become even more accurate and more versatile.