高解析度數位全像顯微系統之研究

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2012

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本論文中主要針對反射式數位全像顯微系統與如何提升數位全像顯微系統的縱向解析度與橫向解析度來進行深入的探討與研究。首先探討有關於反射式數位全像顯微系統拍攝樣本時物鏡的收光問題,系統量測特性與參數,以及量測各種樣本的三維表面輪廓,並與市面上的三維表面輪廓儀(白光干涉儀)比較其系統之間的差異性。接著主要研究工作為探討雷射光源對於離軸式數位全像顯微術之縱向解析度的影響,並考慮在波長穩定雷射光譜下的相位量測表現。在計算系統相位精準度的過程中,當我們使用空間平均與時間平均兩種平均系統相位誤差的方法時,結果發現單模態雷射與多模態雷射之同調特性對於重建相位精準度的影響與差異,進而可將波長穩定技術運用於雷射二極體的單模操作狀態使得數位全像顯微系統的縱向解析度得以提升至次奈米(< 1nm)等級。另一個研究主題為提升系統的橫向解析度,主要是利用合成孔徑原理來進行橫向超高解析度的角度多工推導與模擬,由電腦模擬結果證實使用物光與參考光同時角度多工技術,此時只需拍攝一張數位全像片,即可以達到橫向超高解析度。
In this study, we investigate the imaging properties of reflection-type digital holographic microscopy (DHM) system and how to improve the axial resolution and lateral resolution in the DHM system. First, we study the acceptable radius of curvature and the maximum height of the sample are restricted to the objective lens of reflection-type DHM. Then we present a full-field three-dimensional surface profile technique for measuring the topography of sample. We also describe the influence of coherent illumination on phase measurement accuracy in DHM. To improve net phase accuracy, the spatial and temporal averaging techniques are applied simultaneously to suppress the phase noises caused by the light source and CCD image sensor. A comparison between a laser diode operated in single- and multi-modes on the fringe visibility and the reconstructed phase accuracy is given. Axial sub-nanometer accuracy in DHM is performed using a wavelength-stabilized laser diode in single-mode operation. Another research work is to improve the lateral resolution of the DHM system using synthetic aperture technique. Simulated results show that the angular-multiplexed synthetic aperture can reach superresolution imaging by one-shot in DHM system.

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數位全像術, 三維表面輪廓儀, 單模雷射, 縱向解析度, 橫向超高解析度, Digital holography, 3-D surface profiler, Single-mode laser, Axial resolution, Superresolution

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