差動式光學希爾伯特偵測法對次波長相位之感測

Abstract

摘 要 光學同調斷層掃描術（OCT）是一種利用低同調干涉的原理產生非接觸式且高速斷層影像成像之重要技術，而相位解析光學同調斷層掃瞄術（Phase-Resolved OCT）結合了傳統光學同調斷層掃描術的優點，使斷層影像可呈現奈米尺度的微小相位差異，這是傳統OCT運用取得強度值所無法測得的。 本研究旨在探討運用快速光學延遲掃瞄線；RSOD搭配馬赫-詹德干涉儀（Mach-Zehnder Interferometer）與平衡式偵測之光路架構量測相位，來達成相位解析光學同調斷層掃瞄之架構，並提出差動式光學希爾伯特偵測法（Differential Optical Hilbert Detection Method）取得受測樣品的絕對相位資訊，也針對光學希爾伯特偵測法與差動式光學希爾伯特偵測法兩種取得相位資訊的方法來比較並探討。 關鍵字：相位感測、希爾伯特偵測法。Abstract

Optical coherence tomography (OCT), based on low coherence interferometry, is a powerful tool that can support non-contact and high-speed tomographic imaging in transparent and turbid specimens. Phase-Resolved OCT, combines the advantages of OCT with additional image contrasts obtained by using phase sensitive detection techniques to detect longitudinal displacement with nanometer sensitivity; where these small optical path differences are invisible in conventional intensity-based OCT images. This study presents a phase resolved OCT system by incorporating the rapid-scanning optical delay line (RSOD) and the balanced detection configuration into a Mach-Zehnder interferometer. A differential optical Hilbert detection method was also proposed to support effort to the improvement of measurement sensitivity. The performance of phase measurement capability using different configurations (i.e. optical Hilbert and differential optical Hilbert method) was also compared and analyzed.