title: Fiber-optic nonlinear endomicroscopy with focus scanning by using shape memory alloy actuation.
abstract: A miniature fiber optic endomicroscope with built-in dynamic focus scanning capability is developed for the first time for 3-D two-photon fluorescence (TPF) imaging of biological samples. Fast 2-D lateral beam scanning is realized by resonantly vibrating a double-clad fiber cantilever with a tubular piezoactuator. Slow axial scanning is achieved by moving the distal end of the imaging probe with an extremely compact electrically driven shape memory alloy (SMA). The 10-mm-long SMA allows 150-μm contractions with a driving voltage varying only from 50 to 100 mV. The response of the SMA contraction with the applied voltage is nonlinear, but repeatable and can be accurately calibrated. Depth-resolved imaging of acriflavine-stained biological tissues and unstained white paper with the endomicroscope is performed, and the results demonstrate the feasibility of 3-D nonlinear optical imaging with the SMA-based scanning fiber-optic endomicroscope.
authors.affiliation: Johns Hopkins University, Department of Biomedical Engineering, Baltimore, MD 21205, USA.
authors.forename: Yicong
authors.initials: Y
authors.lastname: Wu
authors.forename: Yuying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jiefeng
authors.initials: J
authors.lastname: Xi
authors.forename: Ming-Jun
authors.initials: MJ
authors.lastname: Li
authors.forename: Xingde
authors.initials: X
authors.lastname: Li
mesh_terms: D000497:Alloys; D055119:Elastic Modulus; D019723:Endoscopes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D007909:Lenses; D055617:Micro-Electrical-Mechanical Systems; D018613:Microscopy, Confocal / Q000295:instrumentation*; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation*; D017711:Nonlinear Dynamics
chemical_list: D000497:Alloys