Fiber type of Optical coherence tomography with auto-focus design

Optical coherence tomography (OCT) is a novel technique for noninvasive imaging based on low coherence interferometer. In order to get image with high resolution, the highly precise scanning and sample stages are essential. In this study, we develop a new optical fiber type of OCT with a commercial auto-focus device to simultaneously measure refractive index and thickness of a single-layer for demonstration. In order to diminish the measurement error resulting from the slight vibration of the sample or sample stage, we design an auto-focus device into the new OCT system. As compared to the conventional one, the new OCT setup is simpler and processes the data speedily. It is found that the conventional OCT with an auto-focus device would be extremely difficult in controlling stages.