Dangpeng Xu, Jianjun Wang, Mingzhong Li, Honghuan Lin, Rui Zhang, Ying Deng, Qinghua Deng, Xiaodong Huang, Mingzhe Wang, Lei Ding, Jun Tang
Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-988, Mianyang, 621900, China.
Opt Express. 2010 Mar 29;18(7):6621-7. doi: 10.1364/OE.18.006621.
The conversion of frequency modulation to amplitude modulation (FM-to-AM) effect is harmful to the high power laser facility based on the phase modulation technique. The FM-to-AM effect of phase modulation pulse induced by the weak etalon effect in wave plates was investigated theoretically and experimentally. A bulk phase modulator with a modulation frequency of 9.2GHz was employed. The numerical simulation results show that the FM-to-AM effect with a temporal modulation depth of 2.5% and 29.7% on the top of the pulse shape was induced by the weak etalon effect in half-wave plate with thickness of 1mm and residual reflectance ratio of 0.5% for 1 pass and 12 passes respectively. On the same condition, the temporal modulation depth is 3.0% and 23.4% respectively in the experiment. The results are in good agreement with numerical simulation results. To our knowledge, it is the first time to introduce the weak etalon effect in wave plates for a complex phase modulation laser system.
频率调制到幅度调制（FM 到 AM）效应对于基于相位调制技术的高功率激光装置是有害的。理论和实验研究了波片中弱标准具效应引起的相位调制脉冲的 FM 到 AM 效应。采用了调制频率为 9.2GHz 的体相位调制器。数值模拟结果表明，对于厚度为 1mm、单次和 12 次通过时残余反射率分别为 0.5%的半波片，弱标准具效应在脉冲形状顶部分别引起了时间调制深度为 2.5%和 29.7%的 FM 到 AM 效应。在相同条件下，实验中的时间调制深度分别为 3.0%和 23.4%。结果与数值模拟结果吻合良好。据我们所知，这是首次在复杂相位调制激光系统中引入波片中的弱标准具效应。
