The depth scanning range of high-resolution OCT is limited by its depth-of-focus (DOF). To solve this problem, we developed a chromatic dual-foci technology to maintain a transverse resolution of 1-2 um over a DOF of about 300 micrometers, which is 2-3 times larger than the single-focus OCT system. In this OCT system, a supercontinuum source is used to provide illumination from 700 to 1600 nm. The interference fringe is detected by a dual-spectrometer system, which engages a Si camera and an InGaAs camera. The Si camera detects the spectral single from 700 to 950 nm, and InGaAs camera covers 1100 to 1600 nm spectral range. As the focal region for long wavelength section is deeper than the short one, the two spectral sections are processed separately to form two OCT images of different depths in the sample. After combining the two images, we obtained DOF extended OCT images.
|