透明介质中强聚焦激光感应等离子体参数控制研究

Research on Parameters of Focused Laser Packet-Induced Plasma in Tranparent Materials

利用广义非线性薛定谔方程,研究了聚焦激光通过透明介质时,感应等离子体的位置、大小及其同激光参数的关系。计算发现:对于给定衍射长度的激光波包,感应等离子体浓度最大值随入射激光功率的增加而趋于一恒定值,感应等离子体区域的大小随着入射激光波包功率的增加而变长、变粗;对于给定功率的激光波包,感应等离子体浓度随着入射激光波包的衍射长度的增加而减少;对于不同衍射长度的激光波包,随着激光功率的增加,感应等离子体向不同方向发展。计算得到的等离子体的位置和形状的变化同Gord ienko等的实验结果非常吻合。该研究有助于理解感应等离子体在介质中的形成过程,推动其在激光加工中的应用。

Using the generalized nonlinear Schrdinger equation,the relation between the laser parameters and the place,size of the plasma induced by a focused laser packet in transparent materials have been simulated.Calculation shows that： the ultimate density of the induced plasma trends towards a constant for a given diffraction length of the laser packet,and the region of the induced plasma becomes larger and longer with the increase of the laser power;for a given power laser packet the density of the induced plasma decreases with the increase of the diffraction length of the laser packet;for laser packets with different diffraction length the region of induced plasma extends to different direction with the increase of the laser power,which is consistent with the experimental results by Gordienko et al..This study may be beneficial to understand the formation of the induced plasma in materials and push forward its application in laser processing.