中文摘要：

利用Nd：YAG脉冲激光在空气中烧蚀Cu靶,产生激光等离子体羽,通过改变离焦量获得相应的等离子体的空间谱;用光谱学方法分析了三种离焦量下空间谱线结构和空间等离子体的电子温度演化规律;并对等离子体光谱的特性和产生机制进行了讨论.结果表明：离焦量对等离子体的谱线强度、谱线结构、电子温度的空间特性都有影响,特征谱强度最大值出现在空间位置1.0mm附近,离焦量为-2mm时电子温度最高.

英文摘要：

The plasma plume have been obtained by Nd：YAG laser ablating a metal copper target in air and the spacialspectra of the plasma were obtained through varying the defocusing distance.Using spectroscopic methods,the spectral structure and electron temperature in various spacial distances from the target was studied.And the plasma spectrum characteristics and mechanism were discussed.The results show that the spectral intensity,spectral structure and electron temperature are closely related with the defocusing distance.The maximum characteristic spectrum intensity appears at 1.0mm spacial position from the target and the electron temperature is highest at defocusing distance of-2mm.