Computational Fluorescence Imaging with Multi-Core Fiber Bundles – Towards High-Speed Imaging Through Bare Optical Fibers

Wavefront control of the coherent lasers has opened a new class of imaging techniques through optical fibers called lensless endoscopes. A spatial light modulator (SLM) at the entrance of an optical fiber modifies the wavefront of a laser beam to undo the scrambling of the initial beams by the fiber and this enables the transport of either illumination patterns or images through the fiber [1]. In the most common implementation, the SLM allows for the generation and the scanning of a single high-intensity focus at the distal end of the fiber with no additional optical elements, analogous to a confocal scanning microscope. This allows for the acquisition of images at a rate only limited by the update rate of the SLM (ranging from a few Hz to
$\sim \text{kHz}$
). This is relatively slow compared to a confocal microscope where pixel dwell times in the
$\mu \mathrm{s}$
regime are routinely obtained. Hence, it remains a significant challenge to speedup the image acquisition rates with lensless endoscopes.