Calibration-free imaging through a multicore fiber using speckle scanning microscopy.

The images produced by multicore endoscopes are pixelated, and their resolution is limited by the core-to-core spacing. Lenses can be used to improve the resolution, but this reduces the field of view proportionally. Lensless endoscopy through multicore fibers can be achieved by using wavefront shaping techniques. This requires a calibration step, and the conformation of the fiber must remain constant over time. Here we demonstrate that, without a calibration step and in the presence of core-to-core coupling, we can obtain fluorescence images with a resolution better than the core-to-core spacing. This is accomplished by taking advantage of the memory effect present in these kinds of fibers.