Space-time division multiplexing-based superfast spectral-domain optical coherence tomography up to 1 MHz A-scan rate

초록

Optical coherence tomography (OCT) is a high-resolution and non-invasive internal structural imaging technique. Since the first introduction of OCT, it has been widely studied to enhance the scanning speed of the system to enhance the applicability. Spectral-domain OCT (SD-OCT) is one of the representative types of Fourier-domain OCT, which consisted with lower prices than swept-source OCT and offers higher axial resolution, but there are limited hardware performance to improve the scanning speed. In this paper, we introduced the space-time division multiplexing (STDM) method-based superfast SD-OCT with 1 MHz A-scan rate. In terms of the time-division method, dual-cameras were implemented in a single spectrometer to reduce the alignment error between each camera and fully utilize the operating time of camera by remove the dead time. In addition, the path length difference of the two-sample arm is accurately controlled to utilize the space-division method. By concurrently integrating the time- and space-division methods in STDM with GPU parallel computing, 32 volume/sec was acquired. The quantitative evaluation of the performance of STDM-OCT was analyzed with sensitivity roll-off and image quality comparison measured at different depth. The proposed STDM-OCT is able to enlarge the application of OCT including biomedical research areas, which require a high-speed scanning system.

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