Gabor fusion technique in a Talbot bands optical coherence tomography system.

In this paper we show how to advantageously combine two effects to enhance the sensitivity with depth in Fourier domain (FD) optical coherence tomography (OCT): Talbot bands (TB) and Gabor-based fusion (GF) technique. TB operation is achieved by routing the two beams, from the object arm and from the reference arm in the OCT interferometer, along parallel separate paths towards the spectrometer. By adjusting the lateral gap between the two beams in their way towards the spectrometer, the position for the maximum of contrast variation of spectral modulation versus the optical path difference in the interferometer is adjusted. For five values of the focus position, the gap between the two beams is readjusted to reach maximum sensitivity. Then, similar to the procedure employed in the GF technique, a compound image is formed by stitching together the parts of the five images that exhibited maximum brightness. The smaller the diameters of the two beams, the narrower the visibility profile versus depth in Talbot bands, which brings advantages in terms of mirror terms attenuation. However, this leads to a larger spot on the linear camera, which introduces losses, therefore the combined procedure, TB/GF is investigated for four different values of the beam diameters of the two beams. Future cameras with larger pixel size may take full advantage of the TB/GF procedure proposed here.