An Electro Thermally Actuated Micro Cantilever Based Fiber Optic Scanner

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.