雙光子激發螢光(two-photon excited fluorescence，TPEF)顯微術能提供高解析度和非入侵式的光學切片效果的影像功效，使得TPEF顯微術在生物醫學影像的應用有極大的發展潛力。本論文以TPEF技術為基礎，搭配光纖光學及壓電式掃描系統，來發展一套全光纖微型內視顯微系統，以達到深入活體體內成像之目的。利用Ti:sapphire飛秒雷射振盪器(femtosecond laser oscillator)作為光源，其輸出波寬為83 fs、重覆率為95 MHz之脈衝雷射，一條雙包覆層光纖(double cladding fiber，DCF)作為傳送激發光和收取非線性發射光之用，此DCF與一個管狀的壓電驅動器結合，形成一個二維的掃描光纖探頭；從光纖探頭射出的雷射光經由三片消色差透鏡鏡組聚焦樣本上；最後利用具750至800nm負色散之光子能隙光纖取代傳統的光柵/稜鏡補償系統以提供負色散來補償整個系統的色散。系統內每個元件的色散值藉由自製的二次自相關儀來量測，再透過Nonlinear Schrödinger方程式模擬雷射光經過整個系統後的變化，以設計出最窄的輸出脈衝雷射。利用光纖在共振頻率工作下能產生最大擺動的特性，可產生一個視野為295μm的螺旋型掃描圖案。

Two-photon excited fluorescence (TPEF) microscopy can provide noninvasive, high-resolution optical sectioning images, and hence has been extended to biomedical imaging. In the thesis, a compact all-fiber endomicroscopy based on TPEF has been developed for providing fast two-dimensional (2D) nonlinear imaging for bio-tissues in vivo. A conventional double-clad fiber is employed for single mode femtosecond pulse delivery and multimode nonlinear optical signals collection. A miniature piezoelectric tube is combined with the double-clad fiber to form a fast 2D beam scanning probe. A Ti:sapphire femtosecond (fs) oscillator as a light source has a pulse width of 83 fs under a repetition rate of 95 MHz. A double cladding fiber (DCF) was utilized to deliver the excitation light and collect the nonlinear emission light. The DCF was then integrated into a piezoelectric tube to form a 2D scanning fiber probe. A compound lens consists of three micro-size doublet achromatic lenses was designed for focusing the laser pulse and collecting nonlinear optical signals with minimum focal shift over the large separation between near infrared excitation and visible nonlinear optical signal collection wavelengths. Finally, a single photonic band-gap fiber with negative group velocity dispersion between 750 to 800 nm was included for pulse prechirping in replacing bulky grating/prism based compressor to compensate the dispersion in the overall system. The dispersion of each component in the system was measured by mean of a home-built second-order autocorrelator. Moreover, a Nonlinear Schrödinger equation was utilized to estimate the lengths of the DCF and photonic band-gap fiber in order to get a minimum pulse width at the output of the system. By driving the scanning probe under its resonant frequency, a spiral scanning with a field of view of 295μm can be generated.

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