Design of spectrometer-based frequency-domain optical coherence tomography at 1300 nm wavelength for skin diagnostics

In this work, we report the optical design and implementation of a high-speed high-resolution spectrometer-based frequency domain optical coherence tomography (FD-OCT) operating at around 1300 nm wavelength. The designed spectrometer utilizes the off-axis parabolic mirrors instead of spherical mirror with the Czerny-Turner configuration. The implemented spectrometer can capture a full spectral bandwidth of over 200 nm around the 1307 nm central wavelength at an acquisition rate of 25,000 spectra per second. When using the spectrometer in our custom developed FD-OCT system, the maximum imaging depth was verified to be about 5 mm with an axial resolution of about 16-21 μm in air. Therefore, we can utilize the system to investigate the under layer of human skin in vivo.