本論文主要研究與發展具有三明治結構之可電控聚合物穩定膽固醇液晶(polymer-stabilized liquid crystal，PSCLC)雷射。此雷射樣品包含三層結構，中間層為染料摻雜向列型液晶(dye-doped nematic liquid crystal，DDNLC)，兩側為PSCLC層。中間層之染料扮演增益介質之角色，外側PSCLC層扮演分佈式布拉格反射鏡之角色，外激產生的螢光可被兩側PSCLC反射於NLC層內達到共振條件，進一步於這些共振模態間的競爭中產生雷射閥值最低之雷射輸出。實驗結果發現，經強紫外光照聚合完成後的PSCLC不僅產生聚合物網路穩固住膽固醇液晶之螺旋結構，且伴隨產生許多正負離子。在外加電壓時，這些離子重新分佈以至於PSCLC內部造成螺距梯度，進而達成反射波帶變寬現象。另外，中間夾層具有水平配向之DDNLC另外具有波板功能，做為半與全波板時，於元件反射波帶內之穿射率分別為最高與最低值，雷射共振模態將會於穿透率最高時獲得。當同時外加相同電壓於兩側之PSCLC時，反射波帶的增寬可造成共振模態數量增加，等效於反射波帶兩側共振模態在頻譜上可往外位移，當施加的電壓越高，兩側共振模態此位移量越大，此時產生的雷射輸出波長位移量也會越大，實驗結果顯示此元件電控雷射輸出位移量最大可達70 nm且電調控特性具有可逆性。此外，本論文也證明在改變DDNLC厚度之下，共振模態會跟著變化，以至於雷射輸出波長可位移量亦會跟著變化。另外，若只使用單種螢光染料則可電控雷射輸出波長之位移量最多僅有51 nm，若使用兩種染料加以混合，使其螢光分布變為更寬廣，則可成功使雷射可電控輸出波長達70 nm。

The thesis mainly investigate and develop electrically tunable polymer-stabilized liquid crystal，PSCLC) lasers with a sandwiched structure. This structure includes three layers: a dye-doped nematic liquid crystal (DDNLC) layer is located in the middle and two identical PSCLC layers are located in between the DDNLC layer, which play roles of gain medium and distributed Bragg reflector (DBR), respectively. The fluorescence photons, obtained by the stimulated dyes by the externality, are confined in the DDNLC layer by the repeated reflection from the DBRs such that some resonant modes can be obtained. Through the competition among these resonant modes by considering the gains and losses for these modes, the lasing output can be obtained with a lowest lasing threshold.Experimental results show that the strong UV light irradiation can lead to the generation of the polymer network that can stabilize the CLC helical structure in the PSCLC but also of lots of positive and negative ions. The ions may redistribute in the PSCLC in the presence of the external voltage such that a pitch gradient can form along the applied field and the reflection band of the PSCLC can become broadening. In addition, the inner homogenously-aligned DDNLC layer plays another role of wave plate. Relatively maximum and minimum transmittance of the PSCLC can be obtained as the DDNLC plays a half- and a full-wave plate, respectively. The resonant modes can occur as the PSCLC has relative maxima. When applying identical voltage on the outer PSCLC layers, the broadening of the reflection band may increase the number of the resonant mode, which result efficiently increases the outward shift of the two resonant modes near the bandedges of the reflection band in spectrum. As the voltage increases, the shift of the two modes becomes larger, resulting in the larger shift of the lasing output. The largest shift for the lasing output of the PSCLC laser can be as large as 70 nm and the electrical tuning is reversible.In addition, the thesis also demonstrates that the lasing wavelength can change with varying the thickness of the DDNLC layer and the fluorescence distribution of the laser dye. The change of the thickness of the DDNLC can change the number of the resonant mode, and thus equivalently change the shift of the lasing wavelength. The fluorescence distribution of two types of laser dye can be more broadening than that of a single laser dye such that the largest amount of lasing tuning can increase from 51 nm to 70 nm.

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