研究摻釹混合釩酸鹽類雷射的自鎖模特性

Abstract

由於鎖模雷射具有可以產生連續穩定的高輸出功率、極短脈衝寬度輸出的特性，使其在科學研究及工業領域都有許多應用，本實驗選用具有良好雷射物理特性的摻釹釩酸類晶體 (Nd:GdxY1-xVO4)作為增益質材料，以結構簡單的凹平共振腔輸出自鎖模雷射脈衝波長在1064nm及1342nm脈衝，並探討其相關特性，作為後續鎖模脈衝雷射設計時參考運用；實驗結果發現輸出脈衝雷射波長在1064nm時，在最大輸入功率7.85W時，得到輸出功率為 2.51W，轉換效率約為31.97%，輸出脈衝形成基本鎖模現象，形成原因為共振腔長所造成，並發現輸出脈衝穩定度與Gd濃度呈反比；輸出脈衝波長在1342nm時，得到輸出功率1.37W，轉換效率為 17.45%，形成諧波鎖模現象，形成原因為增益介質晶體本身抗反射鍍膜，造成標準具效應 (etalon effect) 發生，產生N=3，最高重複率達32.1GHz，脈寬為5.5ps鎖模脈衝雷射，並歸納繪製關係圖，以為後續運用。

Since a continuous stable high power and extremely short pulse width laser output can achieved by mode-locked laser, ultrashort pulse lasers are used in a wide range of areas, both in scientific and industrial. Nd-doped vanadate (Nd: GdxY1-xVO4) crystal as a gain medium of its excellent physical characteristics are chosen in the experiment lasing mode-locked pulse laser with wavelength at 1064nm and 1342nm for investigation their properties in a simple plano-concave laser resonance cavity as a reference for mode-locked laser design use. The experimental results show that the output wavelength at 1064nm,with input power of 7.85W obtain 2.51W output power with conversion efficiency of 31.97%,with the output pulse form fundamental mode-locking phenomenon, because of the resonance cavity length, and found that the stability of the output pulse with Gd concentration is inversely proportional; pulse output at 1342nm wavelength, with the same input power can obtain output power of 1.37W, the conversion efficiency of 17.45%, the formation of harmonic mode-locking phenomenon, formed due to the gain medium crystal anti-reflective coating, resulting in a harmonic mode-locking effect occurs, generating N=3, the highest pulse repetition rate at 32.1GHz, pulse width 5.5ps, and summarize the relationship drawing, for subsequent use.