本論文為月形光斑整合至暗場拉曼系統之接續工作，暗場拉曼系統為以暗場顯微鏡為基礎，加入有傾角的雷射光作為激發光源，原始的暗場顯微鏡需要使用圓環光作為激發光源，因此使用兩片Axicon透鏡組將雷射光束整形成平行圓環光束，在暗場拉曼系統為最直接的方案。然而受到Axicon透鏡的曲面不理想性質影響，無法形成穩定、長距離傳播的平行圓環光束，因而退而求其次採用月形光斑取代平行圓環光斑。本文第一部份為針對不理想Axicon透鏡進行光學模擬來說明無法形成平行圓環光束之原因;第二部份針對暗場拉曼系統的光譜進行後處理，並和傳統拉曼系統比較。
第一部分中說明月形光斑的形成與Axicon透鏡的不理想性質密切相關，將對照實驗拍攝結果與Zemax軟體模擬結果，佐證不理想模型與實際模型相匹配。
第二部份中說明月形光斑激發的暗場拉曼系統透過改良光學系統，能夠優化讀取的拉曼訊號，而拉曼光譜訊號的後處理透過數學演算法運算，可以改善讀取的拉曼訊號，針對實際遇到的問題，提出對應的兩種方法。
一、Whittaker演算法去除基線:
拉曼光譜中，背景基板與暗電流的訊號光譜之疊合稱為基線，當基線相對於目標樣品訊號過強時，會掩蓋目標拉曼特徵，因此，為了去除基線對拉曼訊號的影響，運用Whittaker演算法去除基線。在扣除基線後的訊雜比分析下，透過數值化方式證實暗場拉曼系統有效增強粒子與基板的對比。
二、Savitzky–Golay平滑演算法平滑曲線:
拉曼光譜中，觀察到隨著波長而變化的低震幅雜訊，為了解決低震幅雜訊對拉曼訊號的影響，使用Savitzky–Golay平滑演算法平滑曲線。
在不理想Axicon透鏡的模擬下，成對的Axicon透鏡將雷射整形成月形光斑，透過模擬能預測透鏡組後方對應的月形光斑形貌，可望將其應用於不同設計下的暗場拉曼系統，再搭配Whittaker演算法去除基線來進行訊雜比分析，達到數值化分析系統改良前後的訊雜比差異，亦可以使用Savitzky–Golay平滑演算法平滑曲線，強化光譜中較不明顯的拉曼特徵。

The annular beam is used to be light source in dark-field microscopes; however, collimated beam can’t be shaping to annular beam by paired Axicon lens’ imperfections; thus, crescent beam is substituted for annular ones.
There are two parts of content in the report.
In the first part, we explained why it can’t take shape annular beam by paired Axicon lens’ imperfections. Afterwards, we explained why we choose crescent beam to be being substituted for annular ones, furthermore, collimated beam can be shaped to crescent beam by paired Axicon lens, that is closely related to Axicon lens’ imperfections. We compared simulation result with measure ones, the purpose of study reported in this article was to compare to the effects of annular beam’s size and distribution.
In the second part, we suggest two ways to subtract each noise. The first way is Whittaker baseline method, substrate’s signal and dark-current’s signal belong to baseline (noise), the baseline can’t be ignored; hence, we must solve spectrum’s baseline; Besides, Raman spectrum’s baseline can be solved by Whittaker baseline method; then, spectrum’s signal processing combine this method with signal-to-noise. The second way is Savitzky–Golay smoothing filter. Raman spectrum’s noise can be observed as a function of wavelength; the second way’s method can filter out this noise. After that, Raman spectrum’s characteristic peak is more obvious than which spectrum without filtering.

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