비축수차 및 짧은 시야심도가 개선된 내시경용 고분해능 광간섭단층촬영용 이미징 프루브 개발

Abstract

Endoscopic micro optical coherence tomography (μOCT) is a biological imaging modality which provides high resolution endoscopic three dimensional imaging in vivo. Despite its usefulness, there are following several limitations in practical applications. First of all, cylindrical sheath protecting the probe inherently causes astigmatism. Second, high numerical aperture makes shorter depth of field (DOF). These are critical because astigmatism degrades image quality and short DOF restrains imaging range in axial direction. To address these aforementioned limitations, we developed a new imaging probe incorporating a zone plate pattern and multimode fiber (MMF). One dimensional zone plate pattern was inserted right after GRIN lens to resolve the astigmatism. And self-imaging wavefront division optical system using multimode fiber made coaxially focused multimode beam to extend depth of field. We designed the 1-D zone plate pattern using optical simulation software (OpticStudio, Zemax) and fabricated by direct laser writing technique. We connected optical elements using glass processor (GPX3300, Vytran) and epoxy. Furthermore, we evaluated the performance of our probe by getting point spread function using beam profiler. The proposed probe showed promising performance for improved image quality and imaging range of micro optical coherence tomography.