title: Three-photon excited fluorescence imaging of unstained tissue using a GRIN lens endoscope.
abstract: We present a compact and portable three-photon gradient index (GRIN) lens endoscope system suitable for imaging of unstained tissues, potentially deep within the body, using a GRIN lens system of 1 mm diameter and 8 cm length. The lateral and axial resolution in water is 1.0 μm and 9.5 μm, respectively. The ~200 μm diameter field of view is imaged at 2 frames/s using a fiber-based excitation source at 1040 nm. Ex vivo imaging is demonstrated with unstained mouse lung at 5.9 mW average power. These results demonstrate the feasibility of three-photon GRIN lens endoscopy for optical biopsy.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, 146 Clark Hall, Ithaca, NY 14853, USA ; These authors contributed equally to this work.
authors.forename: David M
authors.initials: DM
authors.lastname: Huland
authors.forename: Kriti
authors.initials: K
authors.lastname: Charan
authors.forename: Dimitre G
authors.initials: DG
authors.lastname: Ouzounov
authors.forename: Jason S
authors.initials: JS
authors.lastname: Jones
authors.forename: Nozomi
authors.initials: N
authors.lastname: Nishimura
authors.forename: Chris
authors.initials: C
authors.lastname: Xu
keywords: (110.2760) Gradient-index lenses; (170.2150) Endoscopic imaging; (180.4315) Nonlinear microscopy