半共焦腔激光二極體泵浦摻釹釩酸釔激光器之不穩定性研究

Abstract

為了研究一般共振腔的穩定性，最近利用線性穩定方法來分析一個描述光束大小與波前曲率半徑的疊代映象。我們發現在穩定區內有一個新的臨界穩定曲線，這個結果是無法直接從光追跡法得到的。因此實驗上，利用半共焦腔激光二極體泵浦的摻釹釩酸釔雷射來證實這個理論結果。我們觀察列在臨界穩定點附近基模輸出功率的下降，而且有高階橫向模與大雜訊的產生。我們相信含非線性效應介質的共振腔，在臨界穩定結構下是產生不穩定現象的原因。

Recently, an iterative map related to the spot size and radius of curvature had been constructed by linear stability analysis to study the stability of a general optical resonator. We found a new critical stable curve within the stable region, which can not be found by ray tracing directly. Therefore, in this experiment, we use a diode-pumped Nd:YVO4 laser to verify this theoretical result. We observed an output power drop around the critical structure accompanied with high-order transverse modes and considerable power fluctuation. We believe that the resonator with nonlinear medium at this critical structure is responsible for the observed unstable phenomena.