克爾透鏡鎖模雷射虛光闌強度的數值研究

Abstract

我們應用ABCD矩陣數值分析來探討在不同的曲面鏡距離下,增益導引對輸 出光點半徑、晶體輸出功率及小訊號增益三者之影響。並觀察具有增益導 引效應及加入克爾效應後增益介質內光點半徑分佈。進一步計算在不同的 曲面鏡距離下,對功率的差動增益,找出最容易鎖模的曲面鏡距離。我們發 現最大差動增益位於穩定區中間,約為3.3*10^-8 W^-1,其大小遠不及於自 起動所需的條件。 In this thesis, we have include gain guiding effect in gain medium and applied ABCD matrix formulism for a Kerr-lens mode- locking laser cavity to numberically caculate the output beam spot size,output power and small signal gain in different curved mirror separation. the total gain changes as a result of redistribution of cavity mode inside the gain medium due to self-focusing effect by hig intensity optical pulses. futher caculation of the differential gain between the initial spikes resulting form mode beating and steady-state continous wave in different curved mirror separation confirms that the most easy mode locking condition is located in the center of stable range where has the maxium differential gain 3.3*10^-8 W^-1. This value is much less than that of self-start condition.