Abstract
A sub-millimeter sized optical scanner driven by electro-thermal actuation is presented. The scanner is composed of a single-mode optical fiber (SMF) with a cantilevered section at its distal tip. The fiber cantilever is electro-thermally actuated near its base in a single direction and excited at resonance to obtain large deflections at the tip of the fiber. Two-dimensional imaging of an object is demonstrated by simultaneously rotating the object while scanning across its diameter. Illumination light from the optical core of the fiber cantilever is projected through a lens onto the object. Reflected light is collected by the same lens and projected onto a photodetector. An image of the object is reconstructed by interpolation of the detected signal. The resolution of the system was measured to be $16~\mu \text{m}$ by imaging a resolution target. The electro-thermal fiber actuator may provide a new technique for scanning in sub-millimeter sized forward-viewing endoscopic catheters.
Highlights
O PTICAL scanners provide a means to sweep a small spot of laser light across an object to be imaged
A scanning fiber endoscope (SFE) is characterized by the presence of a single mode optical fiber resonantly actuated at its base, whose inner core delivers light to the surface being imaged
This paper reports the design of a novel, ultrathin, electrothermally actuated 1D fiber optic scanner vibrating at resonant frequency, which can be packaged within a ∼500μm diameter housing
Summary
O PTICAL scanners provide a means to sweep a small spot of laser light across an object to be imaged. A scanning fiber endoscope (SFE) is characterized by the presence of a single mode optical fiber resonantly actuated at its base, whose inner core delivers light to the surface being imaged. These flexible endoscopes currently allow miniaturization of the distal end to about 1.2 mm. The light emitted from the core of the fiber cantilever is projected on to the object to be imaged and the light reflected by the object is captured by a silicon photodetector It is a natural extension of the work presented here to rotate the scanner assembly within a small stationary tube instead of rotating the object itself to realize a fully 2-D scanning fiber endoscope.
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