High-speed, long-range and wide-field OCT for in vivo 3D imaging of the oral cavity achieved by a 600 kHz swept source laser.

We report a high-speed, long-range, and wide-field swept-source optical coherence tomography (SS-OCT) system aimed for imaging microstructures and microcirculations in the oral cavity. This system operates at a scan speed of 600 kHz, delivering a wide imaging field of view at 42 × 42 mm and a ranging distance of 36 mm. To simultaneously meet the requirements of high speed and long range, it is necessary for the k-clock trigger signal to be generated at its maximum speed, which may induce non-linear phase response in electronic devices due to the excessive k-clock frequency bandwidth, leading to phase errors. To address this challenge, we introduced a concept of electrical dispersion and a global k-clock compensation approach to improve overall performance of the imaging system. Additionally, image distortion in the wide-field imaging mode is also corrected using a method based on distortion vector maps. With this system, we demonstrate comprehensive structural and blood flow imaging of the anterior oral cavity in healthy individuals. The high-speed, long-range, and wide-field SS-OCT system opens new opportunities for comprehensive oral cavity examinations and holds promise as a reliable tool for assessing oral health conditions.