橢圓偏振干涉儀整合量測平台之設計與研製

Abstract

本研究延續團隊之AVIDTM(Advanced Vibrometer/Interferometry Device)與OBMorph(Opto-BioMorphin)光生化檢測儀開發經驗，建立一新型橢圓偏振干涉儀整合量測平台，以正交偏振光之共光程架構所得正交差動訊號進行橢偏參數求解，並利用表面電漿共振效應增加量測靈敏度，搭配稜鏡耦合以角度調制和相位調制擷取反應訊號。本研究引入雙模態偏振光共光程概念，利用不同偏振態其共振效應之差異，減少實驗校正步驟以克服環境擾動、溫度及機械振動等影響。藉由容錯式解相位演算法，成功地利用映射呂薩加圓歸一化光強量測值，同時驗證圓偏光干涉儀架構量測橢偏參數的可行性。本系統以拋物非球面反射鏡與球面反射鏡之變角度入射子系統為基礎，其有效入射角度為32-70度，可精準控制至10^(-3)度等級，不僅大幅縮小系統體積，同時具有較佳的動態量測範圍、超高解析度(具有折射率變化小數點下四位之解析度)及抗高頻電子訊號干擾等優點，可達到即時薄膜厚度量測、樣本折射率改變及生化反應所造成光學性質改變量測。 透過不同濃度之葡萄糖溶液與酒精混合溶液進行相位測試，定出系統靈敏度及系統解析度分別為8.2×10^6(1⁄RIU)和1.22×10^(-7)(RIU)，並完成非生物樣本重覆性量測、生物樣本如C型反應蛋白(CRP，C-reactive protein)與Anti-CRP專一性生化反應及結核病抑制藥物-DHFR (Dihydrofolate reductase)分子在不同濃度下之相位量測。 另外本研究提出以角度調制與調變銦錫氧化物ITO (Indium tin oxide)薄膜之等效光學特性，解決傳統相位量測動態範圍不足的缺點，以實驗驗證於系統中施加DC與AC 電壓時所量測出ITO層等效折射率變化，與未調變前比較可得到3倍的動態量測範圍擴展。本研究之貢獻在於建立一整合量測平台以達到快速且準確的橢偏參數量測、相位量測與表面電漿共振角量測，作為在液相及固相下樣本之光學特性及物理、化學特性分析的依據，以期未來應用於薄膜製程即時監測與臨床醫學檢測。

Based on previous studies and works on the development of AVIDTM (Advanced Vibrometer/Interferometry Device) and OBMorph (Opto-BioMorphin) systems, a newly developed interferometric ellipsometer integrated with a quadrature interferometer was designed and constructed for ellipsometry measurement. By using one set of orthogonal signals, the circularly polarized ellipsometer incorporated prism-based coupling and paraboloidal mirror based varying incident angle subsystem can undertake angular interrogation and phase interrogation simultaneously. Combining surface plasmon resonance effect, the sensitivity of the measuring system efficiently increases upon a p-s common path configuration by means of the different response versus the polarization variation. By adopting fault tolerance algorithm (FTA) to normalize the orthogonal signals, the possibility of using the quadrature signal to retrieve ellipsometric parameters and the remap of Lissajous curve to modify the measured outputs were verified experimentally. The FTA allows our implementations to circumvent the misalignment-induced error signals caused by mechanical vibration and to simplify the complicated recalibrations associated with conventional ellipsometry. On the basis of a paraboloidal and on companion spherical mirrors, the precision of angular control subsystem achieves 10^(-3) order when ranged from 32 to 70 deg. The significant features of our system are miniaturization, high sensitivity, high resolution (to the fourth digit order), wide dynamic range, and real-time monitoring in order to measure the thin-film structure and biomolecular interactions fast and precisely. The phase detection on different concentration of glucose solution and alcohol solution represented its sensitivity and resolution over 8.2×10^6(1⁄RIU) and 1.22×10^(-7)(RIU), respectively. Meanwhile, the specific and non-specific reactions such as CRP and anti-CRP and tuberculosis inhibitor-DHFR to protein were measured and verified experimentally. Besides, this dissertation advanced an efficient way to extend the dynamic range upon angular interrogation and the modulation of equivalent index change on ITO (indium-tin-oxide) film layer caused by the change of surface plasmon coupling as the externally DC and AC voltage applied. Our experimental data showed three times extending of dynamic range was reasonably practicable while compared with the traditional phase detection. The fourth digit order variations of equivalent indices on ITO can be observed and be enough to overcome the lack of dynamic range for point-wise measurement. In this dissertation, we advanced and designed a new implementation for interferometry and ellipsometry to enable fast and precise measurements under solid or liquid surroundings. The long-term goal of this work will be on real-time monitoring of thin-film manufactures and clinically biomedical diagnosis