title: High-resolution, lensless endoscope based on digital scanning through a multimode optical fiber.
abstract: We propose and experimentally demonstrate an ultra-thin rigid endoscope (450 μm diameter) based on a passive multimode optical fiber. We use digital phase conjugation to overcome the modal scrambling of the fiber to tightly focus and scan the laser light at its distal end. By exploiting the maximum number of modes available, sub-micron resolution, high quality fluorescence images of neuronal cells were acquired. The imaging system is evaluated in terms of fluorescence collection efficiency, resolution and field of view. The small diameter of the proposed endoscope, along with its high quality images offer an opportunity for minimally invasive medical endoscopic imaging and diagnosis based on cellular phenotype via direct tissue penetration.
authors: School of Engineering, École Polytechnique Fédéral de Lausanne (EPFL), Station 17, Lausanne,  Switzerland.
authors: Ioannis N
authors: IN
authors: Papadopoulos
authors: Salma
authors: S
authors: Farahi
authors: Christophe
authors: C
authors: Moser
authors: Demetri
authors: D
authors: Psaltis
keywords: (070.5040) Phase conjugation; (090.1995) Digital holography; (110.2350) Fiber optics imaging; (170.0110) Imaging systems; (170.2150) Endoscopic imaging; (170.7050) Turbid media