A Single Fiber Resonating Piezoelectric Scanner For Microscopy

For promoting the utilization of scanning optical microendoscopy, this dissertation deployed deep investigations on the key scientific and technological issues about a sort of scanners. We breakthrough the present method-which is with blindness and without effective guidance-of the research and development of the single fiber resonating piezoelectric scanner. We clarify the key issues of the mechanism, point out the determinants of the scanner and provide criterions for development, design, fabrication, and evaluation of the scanner.The main research contents and creative points are as follows:1). We investigated the effect of the material parameters of parts of the scanner on the deformation and vibration parameters, and gave the quantitive results. The displacement of the piezoelectric square tip is in direct proportion to the square of the patch length, direct proportion to the piezoelectric coefficient and applied electric field, negative correlation to the width and thickness of the piezoelectric patch. The resonant amplitude of the fiber cantilever is inverse proportion to the square of the fiber diameter, inverse proportion to the square root of the fiber length, inverse proportion to the square root of the elastic modulus.2). We use the finite element method, build the coupled field model, simulate the system numerically, and analysis the mechanical properties in high precision. We obtained the first forty modalities of the scanner, indentified that the resonant modalities of the scanner include string vibration, cantilever vibration, square torsion, square vibration, and radio expansion, among which the cantilever vibration is suitable for scanning imaging. We achieved the frequency response in the0-14kHz spectrum. We analyzed the behavior of the scanner with inertia and damping, obtained50transient state of the spiral scanning and60transient state of the Lissajous scanning.3). We design and fabricate three kinds of scanners for three different applications. First, we develop a spiral scanning low voltage driven miniaturized scanner. The required driving voltage is10V peak-to-peak voltage. The diameter of the scanner is2mm. Second, we propose a method for the scanner to achieve a raster pattern by producing different order resonances in the two orthogonal directions. The raster pattern is much more uniform in terms of spatial coverage and sampling time than the spiral pattern. The scanner has a line rate of879Hz and a frame rate of3Hz. Third, for achieving a forward-imaging nonlinear optical micro-endoscope (NOME) with improved optical characteristics, we use an home-made piezoelectric actuator to drive the double-clad photonic crystal fiber (DCPCF). The output pulse is175fs under52mW. The diameter of the integrated probe is3.5mm. It is the first time for the miniaturized single fiber resonating piezoelectric scanner to drive the350μm fiber to achieve1mm vibration.In a word, we carried both basic and applicable researches on the single fiber resonating piezoelectric scanner for optical microscopy. We discussed the key issues of the scanning mechanism, raised a complete set of implement plans, achieved the prototype, and accomplished the scanning imaging. We provided a foundation for promoting various applications of the single fiber resonating piezoelectric scanner.