Cross-free in both lateral and axial directions for Fourier-domain full-field optical coherence tomography

Abstract

Fourier-domain full-field optical coherence tomography (FD-FF-OCT) has the advantages of high resolution and parallel detection. However, using parallel detection can result in optical crosstalk. Toward minimizing crosstalk, we implemented a very fast deformable membrane (DM) that introduces random phase illumination, which can effectively reduce the crosstalk by washing out fringes originating from multiply scattered light. However, for one thing, although the application of DM has reduced the crosstalk problem in parallel detection to a certain extent, there will still be a lot of background noises, which may come from the circadian rhythm of the sample and multiple scattered photons. The problem could be solved by employing the adaptive singular value decomposition (SVD) filtering. We also combined SVD with the cumulative sum method, which can improve image resolution well. For the other thing, the random phase introduced by DM in the spectral domain will cause axial crosstalk after inverse Fourier transform. As far as we know, we are the first team to notice axial crosstalk and proposes that this problem can be solved by controlling the deformation range of DM. We have carried out a theoretical analysis of the above methods and verified its feasibility by simulation.

Time domain ptychographic full field optical coherence tomography

“…Compared with SS-OCT, POCT eliminates the interferometer and has a simpler structure. However, POCT also has some disadvantages, such as crosstalk and reduced detection depth, because the sweep-source is an instantaneous narrow-band light source with longer coherence length within the sampling period and uses parallel detection [21,22]. TD-POCT uses a broadband light source and pinhole detection, which means the coherence length in the sampling period is very small (micron level) and the crosstalk is greatly limited, so the effect of the spatial coherence gate makes the crosstalk less obvious than POCT.…”