本論文以非線性光學為基礎，透過雙光子以及二倍頻顯微術，開發三維非線性光學內視鏡。實驗以GriffinTM Ti:sapphire飛秒雷射震盪器作為激發光源，透過一條雙包覆層光纖，利用單模中心傳導激發光，以及多模態包覆層來作為收取螢光之用。三個消色差透鏡用來解決激發光源與螢光之色差，藉此提升收光效率。此色差造成在光纖上的激發光與螢光位置不符，使得螢光無法有效傳到至光纖內，進而降低收光效率。利用光柵能產生負色散的特性，來補償整個系統所產生之正色散，完成色散補償，減少因脈衝被拉寬所造成之激發效率降低。透過壓電管與光纖結合，並驅動適當的電壓，使得光纖在共振頻率上產生震盪，完成掃描之目的。利用不同驅動模態，產生兩種二維掃描方式，分別為螺旋掃描與Lissajous掃描，產生一個在空間上完整填滿的圖形，並擷取二維非線性光學影像。螺旋掃描提供150 μm的視野，幀速度5 Hz，影像像素為"290×290" ，並使用共振頻率905 Hz來驅動。Lissajous掃描產生了相同的視野與影像像素，幀速度為1 Hz，形成矩形的影像與較低的光傷害，並使用接近共振頻率的兩個不同電壓來做驅動。最後透過壓電微型馬達來進行軸向移動，達到三維移動之目的。

A miniature and flexible scanning endoscope based on nonlinear optics has been developed for three-dimensional (3D) optical imaging, such as two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging. A double-cladding fiber is employed to transport femtosecond laser pulses to excite samples in single-mode and collects the nonlinear optical signal by multi-mode. For To improve the collection performance, an assembly of three micro-size doublet achromatic lenses were designed by achieving minimum focal shift between the near infrared excitation and visible collection wavelengths. A grating pair with negative group velocity dispersion (GVD) is utilized to compensate the dispersion induced by the optical fiber. Furthermore, a miniature piezoelectric tube is used to produce the space-filling scanning to achieve two-dimensional optical nonlinear images. Two scanning patterns based on spiral scanning and Lissajous scanning are developed via different driving modes. The spiral scanning provides the field of view approximately of 150 μm, pixels of 290×290, frame rate at 5 Hz, and natural resonance frequency at 905 Hz. The Lissajous scanning based on two driving frequencies close to the resonance frequency offers the same field of view and pixels, frame rate at 1 Hz, rectangular images, and low photodamage. Finally, the z-axis piezoelectric motor is integrated into the system to develop a 3D nonlinear optical endoscope.

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