We present a proof-of-concept for side-viewing endoscopic optical coherence tomography probes designed for real-time imaging. The design employs a commercial rotating micro-engine (Kinetron), with a 1 mm outer diameter and maximum speed of 10,000 rpm, to steer the beam from a GRIN lens-terminated optical fiber (Agiltron), 360 degrees around the probe body. The engine is encapsulated inside a PET tube with an outer diameter of 1.6 mm, and coupled to a swept-source based optical coherence tomography (SS-OCT) system operating at 1300 nm with an A-scan rate of 100 kHz.
Large material dispersion mismatch between the reference and sample arms, which would otherwise degrade the axial resolution, is compensated for by using the Master-Slave OCT technique to process the interferograms. This allows for more convenient interchange of probes without exactly matching the fibre length. The probe can be configured using GRIN lenses at the end of the fibers with different focal lengths, and the fiber lengths can differ by several cm. When the probe is changed, the reference path is adjusted, but no dispersion compensation is needed, due to use of the Master Slave method developed by our group. We will demonstrate the performance of such systems with full 360 degree tomographic images of scattering phantoms taken at different probe driving speeds, with different configurations of the probe heads.
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