title: Thermomechanical Actuator-Based Three-Axis Optical Scanner for High-Speed Two-Photon Endomicroscope Imaging.
abstract: This paper presents the design and characterization of a three-axis thermomechanical actuator-based endoscopic scanner for obtainingex vivotwo-photon images. The scanner consisted of two sub-systems: 1) an optical system (prism, gradient index lens, and optical fiber) that was used to deliver and collect light during imaging and 2) a small-scale silicon electromechanical scanner that could raster scan the focal point of the optics through a specimen. The scanner can be housed within a 7 mm Ø endoscope port and can scan at the speed of 3 kHz × 100 Hz × 30 Hz along three axes throughout a 125 × 125 × 100μm3volume. The high-speed thermomechanical actuation was achieved through the use of geometric contouring, pulsing technique, and mechanical frequency multiplication (MFM), where MFM is a new method for increasing the device cycling speed by pairing actuators of unequal forward and returning stroke speeds. Sample cross-sectional images of 15-μm fluorescent beads are presented to demonstrate the resolution and optical cross-sectioning capability of the two-photon imaging system.
authors: Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong.
authors: Shih-Chi
authors: SC
authors: Chen
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
authors: Heejin
authors: H
authors: Choi
authors: Department of Mechanical Engineering, and the Department of Biological Engineering Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
authors: Peter T C
authors: PT
authors: So
authors: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
authors: Martin L
authors: ML
authors: Culpepper
keywords: Thermomechanical actuators; endomicroscope; mechanical frequency multiplier; optical scanner; two-photon excitation