Multimode fiber enables control of spatial coherence in Fourier-domain full-field optical coherence tomography for in vivo corneal imaging

Optics Letters 2021 | Vol. 46, No.6 | 1413-1416

Auksorius, E., Borycki, D., & Wojtkowski, M.


Fourier-domain full-field optical coherence tomography (FD-FF-OCT) has recently emerged as a fast alternative to point-scanning confocal OCT in eye imaging. However, when imaging the cornea with FD-FF-OCT, a spatially coherent laser can focus down on the retina to a spot that exceeds the maximum permissible exposure level. Here we demonstrate that a long multimode fiber with a small core can be used to reduce the spatial coherence of the laser and, thus, enable ultrafast in vivo volumetric imaging of the human cornea without causing risk to the retina.

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Fig. Filtering out fiber-induced speckles in corneal images. Filtered B-scan image, shown in the linear scale on the bottom right, reveals the corneal structure in its entire thickness that was masked by the speckle pattern shown in the top right image. The OCT image was derived from a single volume acquired in 8.6 ms.
This project has received funding from the European Union’s
Horizon 2020 research and innovation programme
under grant agreement No 666295.