Extended field-of-view in a lensless endoscope using an aperiodic   multicore fiber
  We investigate lensless endoscopy using coherent beam combining and aperiodic multicore fibers (MCF). We show that diffracted orders, inherent to MCF with periodically arranged cores, dramatically reduce the field of view (FoV) and that randomness in MCF core positions can increase the FoV up to the diffraction limit set by a single fiber core, while maintaining MCF experimental feasibility. We demonstrate experimentally pixelation-free lensless endoscopy imaging over a 120 micron FoV with an aperiodic MCF designed with widely spaced cores. We show that this system is suitable to perform beam scanning imaging by simply applying a tilt to the proximal wavefront. 
Siddharth Sivankutty, Viktor Tsvirkun, G\'eraud Bouwmans, Dani Kogan,   Dan Oron, Esben Ravn Andresen and Herv\'e Rigneault
physics.optics