激光诱导放电等离子体羽辉的研究

Investigation of plume of laser-induced discharge plasma

为了研究激光诱导放电等离子体的膨胀特性,建立了一套基于脉冲CO2激光诱导锡靶放电等离子体极紫外光源装置,采用增强型电荷耦合器件对羽辉进行拍摄,并采用1维真空电弧模型对实验结果进行了理论说明。实验中改变放电电压和激光能量,得到了不同条件下时间分辨的羽辉图像。结果表明,在激光能量140mJ、放电电压10kV的条件下,获得了稳定的放电等离子体;等离子体的羽辉形态与电流存在对应关系,经历了形成、膨胀、收缩、再次膨胀和消散的不同阶段,放电电压和诱导激光能量对羽辉大小、稳定性和形成时间有影响。此研究有助于提高激光诱导放电等离子体光源的稳定性以及极紫外光的输出功率。

In order to study the expansion characteristics of laser-induced discharge plasma(LDP),a set of extreme ultraviolet source for tin target discharge plasma based on pulsed CO2 laser was established.The plume was photographed by intensified charge-coupled device.1-D vacuum arc model was used to explain the experimental results.The time-resolved plume images under different conditions were obtained by changing the discharge voltage and laser energy.The results show that,under the condition of 140mJ laser energy and 10kV discharge voltage,a stable discharge plasma was obtained.There is a corresponding relationship between the plume morphology and the current.It has undergone different stages of formation,expansion,contraction,re-expansion and dissipation.Discharge voltage and induced laser energy have effects on plume size,stability and formation time.This study is helpful to improve the stability of LDP source and the output power of extreme ultraviolet light.