飞秒激光与固体靶相互作用中光辐射时间特性的实验研究

为了探索光辐射的时间特性, 在100 TW掺钛蓝宝石飞秒激光器上利用光学条纹相机, 分别在靶背表面法线方向测量了光辐射的时间积分和时间分辨成像光斑. 实验测量结果显示: 光辐射时间积分成像光斑呈长条状, 而辐射区域有发散角、有光强分布, 包含多种辐射成分; 光辐射的时间分辨成像光斑进一步证明, 渡越辐射(TR) 是信号强而快, 持续时间短, 为皮秒(ps) 量级, 是最先到达屏幕上, 并推算出相应的持续时间为85.5ps. 其他成分光辐射是信号弱而慢, 持续时间长, 为纳秒(ns) 量级, 是最后到达屏幕上. 光辐射的时间特性能为鉴别和判断TR信号提供了新的依据.

Experimental study of time characteristic of optical radiation in femtosecond laser interaction with solid targets

In this paper, the time-integrated image pattern of spatial distribution and time-resolved image of optical radiation are measured in the normal direction from the rear side of targets by employing optical streak camera on the 100 TW femtosecond laser facility. The image pattern of spatial distribution presents a strip-shape: the region of optical radiation has a radiation angle and optical intensity distribution, and contains various components; the time-resolved image of optical radiation presents the time-resolved pattern of the optical radiation, witch further proves that the transition radiation is intense, which has short duration (ps) and correspouns to duration of TR of 85.5 ps. and other optical radiations are weak, which have very long duration (ns). The time-resolved characteristic of optical radiation can provide new evidence for discrimination and judgement of TR.