膽固醇液晶之螺旋結構排列具有一維的週期性，並且其週期單位在光波長尺度下，因此我們可視其為＂一維的光子晶體＂。由於光波與電子的波函數都是機率波，因此光在光子晶體中的波形，應該類似於電子在物質內分佈的模式。因為膽固醇液晶具有光子晶體特性，其結構提供分佈回饋的效果即如同共振腔，在添加雷射染料於膽固醇液晶後，經由適當激發下，可成為一個不用外加共振腔的雷射原件。
本論文分成三個部份，第一部分利用Nd-YAG 調Q 脈衝雷射激發膽固醇液晶產生多點雷射輸出，結果成功的觀察到被激發出的多點膽固醇雷射，應用這個結果在之後兩個部份實驗。
在第二部份中，嘗試將多點膽固醇液晶雷射和光配向技術結合，達到被激發出的膽固醇雷射輸出能和光配向的圖形一致，不過最後的結果並未達到預期的效果。主要的原因在於我們參雜了兩種染料在液晶盒中，一種是光配向用的偶氮染料甲基紅，一種是雷射染料DCM，而甲基紅的吸收光譜和DCM 的放射光譜重疊到，表示DCM 放射出的光會被甲基紅吸收耗損。因此，在DCM 放射頻譜和膽固醇液晶反射波段能係邊緣有適當的疊合，無法產生膽固醇液晶雷射輸出。即使加強入射Nd-YAG雷射的能量使DCM 放射能量增加，但無法大過甲基紅的耗損，因此依舊無法產生膽固醇液晶雷射輸出。
在最後一部份中，我們再以溫度調控膽固醇液晶的反射頻譜，藉由單邊加熱樣品溫度產生膽固醇液晶的螺距達到梯度變化，然後用Nd-YAG雷射產生不同光波雷射輸出多點激發樣品，我們成功的觀察到多波長的膽固醇雷射被激發出來。實驗中分為兩部分，一種是利用膽固醇液晶的螺旋扭轉力和液晶折射率隨溫度變化，使膽固醇液晶反射頻譜隨溫度變化。另一種是在室溫下加入超過液晶可溶解的手性分子，藉由增加溫度加大溶解度達到膽固醇液晶反射頻譜的調控，從實驗的結果中得知，以增加溫度加大溶解度的方法所調控膽固醇液晶反射頻譜的效果最好，可同時激發出的膽固醇雷射波長範圍可達到65 nm。

Cholesteric liquid crystal (CLC) aligned in a planar texture whish has periodic dielectric structures with periodicity in the range of optical wavelengths which is considered as an one-dimensional (1-D) photonic crystal (PC). Thus ,CLC doped with a laser dye is expected to lase ,when it suitable overlap between emitting spectrum of laser dye and CLC bend gap.
There are three parts in this dissertation. In fist part, we try to lase multi-spot beam from a planar CLC doped with a laser dye pumped by a Q-switch Nd-YAG pulsed laser (Second Harmonic Generation (SHG) λ=532 nm). We are successful to obtain multi-spot laser emitting. This result is then applied for latter two experiments.
In the second part, we firstly fabricate a planar cholesteric LC film doped with a laser dye having a designed pattern using a photoalignment method. We then try to lase the film to emit the designed pattern. The result is not successful. The cause is believed that the overlap between absorption spectrum of photoalignment dye and emission spectrum of laser dye. The result is still not successful, even if we increase energy of Q-switch Nd-YAG laser to enhance emitting energy of laser dye.
In the last part, we use two ways to tune the reflective spectrum of CLC by controlling the temperature of the sample. First way which we used is the changes of helix twist power of CLC and index of liquid crystal with temperature. The other way is dope chiral beyond the maximum solubility of CLC at room temperature. The CLC film results in a gradient pitch change by contacting one substrate of the sample with a heater. Being pumped by a Q-switched Nd-YAG laser, we observe a multi-wavelength of CLC lasing successfully. In the experiment of doping chiral beyond the maximum solubility of CLC at room temperature, the spectrum of the CLC lasing which is the best in our result is 65 nm.

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