High-speed en-face optical coherence tomography system for the retina

We previously reported en-face Optical Coherence Tomography (OCT) images of the retina using a pair of galvanometer scanners. Unfortunately, the relative low speed of galvanometer scanners has limited the acquisition to 2 frames a second. In order to reach video rate acquisition, we evaluated a resonant scanner at 4 kHz with the aim to replace the galvo-scanner which determined the line in the raster image. In the presented work we evaluated the bandwidth required to generate sufficient lateral size images using such a resonant scanner. The spectrum of the photodetected OCT signal is analyzed depending on the position of the optical beam relative to the axis of rotation of the mirror centred or offset.