| Summary: | 碩士 === 國立陽明大學 === 生醫光電工程研究所 === 96 === Based on low-coherence interferometry and optical heterodyne technique, we presented a novel differential-phase optical coherence reflectometer (DP-OCR) by integrating analog differential-phase demodulation technique with conventional envelope detection method. We use DP-OCR to measure the surface profile of an optical grating and the translational speed of a slightly tilted mirror. The experimental results demonstrate the well performance of DP-OCR. We then modify the system to become a common-path configuration, called the differential-phase polarization sensitive optical coherence tomography (DP-PSOCT), which provides better phase stability (0.53˚) and common phase noise rejection mode for differential-phase measurement. Assessing tissue birefringence with this imaging modality could improve the characterization of tissue pathology. We utilize this method to measure the backscattered intensity and birefringence property (phase retardation) of a bovine tendon to demonstrate its capability. We also use DP-PSOCT to image thermal and radiation effects to the birefringence in a fresh bovine tendon. The experimental result shows that thermal effect is critical to the birefringence change, but radiation effect is not effective to the birefringence. Consider the combined thermal and radiation effect, thermal effect is obvious in low dose radiation, but in higher dose the thermal effect is not evident to the birefringence change.
|
|---|
