一般傳統雷射產生的機制是透過固定的反射鏡來作為共振腔，而隨機雷射則是藉由散射介質來形成一個類似共振腔結構的封閉散射迴路，使得光可以透過封閉散射迴路而產生雷射光。隨機雷射之優點在於製作簡單、元件尺寸小、製作成本低、可多方向及多頻率輸出等，已成為近年來的主要研究目標，且可應用於雷射成像、醫療檢測、液晶顯示器或照明系統上。
本論文研究摻雜二氧化矽奈米粒子之聚合物薄膜之隨機雷射特性，我們藉由改變外界環境溫度及施加外力於薄膜樣品來探討對雷射輸出頻譜的影響。實驗發現，透過添加二氧化矽奈米粒子在薄膜樣品內能夠有效地產生封閉散射路徑，並能成功地激發共振型隨機雷射，所量測到的臨界脈衝值約為29.91μJ/mm2。另外，我們透過添加不同濃度之二氧化矽奈米粒子在薄膜樣品內，並由實驗量測得知添加濃度為0.2wt%的二氧化矽奈米粒子時會有最好的雷射輸出。接著，我們藉由溫控器調整外在環境溫度，可以發現不同二氧化矽奈米粒子濃度之薄膜樣品的輸出皆可以由共振型隨機雷射變為非共振型隨機雷射，而雷射的輸出強度及輸出波長位置也會隨溫度而有變化。最後，利用施加外力在不同濃度二氧化矽奈米粒子之薄膜樣品，可以得知輸出頻譜同樣會由共振型隨機雷射變為非共振型隨機雷射，且輸出強度會隨薄膜樣品曲率變大而減弱。

Compared to traditional lasers which need fixed reflection mirrors to form a cavity, random lasers can be generated by using scattering materials to form cavity-like multiple scattering loop paths. There are several unique advantages of random lasers, such as simple fabrication process, small size, low cost, multiple lasing wavelengths, broad solid angle of lasing output. In recent years, random lasers have been employed in speckle-free imaging, medical diagnostics, liquid crystal display and illumination system.
In this thesis, we demonstrate a random laser from a UV curable gel film consisting of silicon dioxide nanoparticles. The lasing properties of random lasers are discussed by changing the surrounding temperature and pressing the sample. In order to obtain appropriate concentration for the lasing action, we change the concentration of the silicon dioxide nanoparticles in the polymer film. Experimental results show that the 0.2wt% doping concentration of silicon dioxide provides better lasing action, and the lasing threshold is approximately 29.91μJ/mm2.
We then vary the temperature to change the random lasers from the coherent feedback to incoherent feedback with the raising operation temperature. In addition, the emission intensity and the lasing peak are also varied by the operation temperature. Finally, we also observe that the emission can be switched between the coherent feedback and the incoherent feedback by applying the external force, and the intensity and the lasing peak are varied by the curvature of the polymer film.

誌謝 i
中文摘要 ii
Abstract iii
目錄 iv
表目錄 vi
圖目錄 vii
第一章 緒論 1
1.1 雷射簡介 1
1.2 隨機雷射簡介 4
1.2.1 隨機雷射之理論及應用 5
1.2.2 可調控之隨機雷射 6
1.2.1 薄膜隨機雷射 10
1.3 研究動機 12
第二章 材料特性及樣品製備與量測 13
2.1 實驗材料介紹 13
2.2 樣品製備 16
2.3 隨機雷射量測架設 19
第三章 添加二氧化矽奈米粒子之聚合物薄膜隨機雷射 21
3.1 聚合物薄膜樣品輸出頻譜之量測 21
3.2 聚合物薄膜樣品添加二氧化矽奈米粒子之輸出頻譜量測 24
3.3 不同濃度之二氧化矽奈米粒子對薄膜樣品輸出頻譜的影響 28
第四章 改變外在環境對添加二氧化矽奈米粒子聚合物薄膜之影響 35
4.1 外界溫度對不同濃度的薄膜樣品輸出頻譜之量測 35
4.2 施加外力對不同濃度的薄膜樣品輸出頻譜之影響 44
第五章 結論與未來展望 51
參考文獻 52

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