Quasi-simultaneous en-face imaging using low coherence interferometry

We report a novel imaging procedure and a system implementing it, capable of acquiring two quasi-simultaneous en-face images from a multi-layer target using a single mode fiber optic interferometer. Two optical sources are employed, which are toggled on and off simultaneously with the ramp signal applied to the scanner whose movement determines the line in the raster image. In this way, half of the line in the final frame is generated by a particular source only. Imaging with two different depth resolutions or with two different wavelengths is made possible in this way. Because the switching is much faster than the observer eye can follow, the two images can be interpreted and compared simultaneously. The paper discusses the different functionality of the system depending whether the OCT image is made out of A or T-scans.