title: Ultra-thin rigid endoscope: two-photon imaging through a graded-index multi-mode fiber.
abstract: Rigid endoscopes like graded-index (GRIN) lenses are known tools in biological imaging, but it is conceptually difficult to miniaturize them. In this letter, we demonstrate an ultra-thin rigid endoscope with a diameter of only 125 μm. In addition, we identify a domain where two-photon endoscopic imaging with fs-pulse excitation is possible. We validate the ultra-thin rigid endoscope consisting of a few cm of graded-index multi-mode fiber by using it to acquire optically sectioned two-photon fluorescence endoscopic images of three-dimensional samples.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Sivankutty
authors.forename: Esben Ravn
authors.initials: ER
authors.lastname: Andresen
authors.forename: Rosa
authors.initials: R
authors.lastname: Cossart
authors.forename: Géraud
authors.initials: G
authors.lastname: Bouwmans
authors.forename: Serge
authors.initials: S
authors.lastname: Monneret
authors.forename: Hervé
authors.initials: H
authors.lastname: Rigneault
mesh_terms: D003952:Diagnostic Imaging / Q000295:instrumentation*; D019723:Endoscopes; D021621:Imaging, Three-Dimensional; D007834:Lasers; D017785:Photons