超短脉冲激光辐照固体靶背向光发射的测量

利用光学CCD相机和OMA光学多道分析仪，分别在金属箔背表面法线方向测量了光发射的积分成像光谱和散射光光谱。积分成像光谱测量结果显示，光谱呈圆环状，在圆环边缘附近出现局部化明亮光信号确定为超热电子输运穿越固体靶引起的光学渡越辐射(OTR);散射光光谱测量结果显示，光谱在300～500 nm之间出现一系列非周期锐利尖峰，在400 nm(2ω)附近出现的尖峰归结于v×B加热机制产生的超热电子束中的聚束引起的相干渡越辐射(CTR)。渡越辐射光强随靶厚度的增加而减小。

A Measurement of Optical Emission from the Rear Surface with Solid Targets Irradiated by Ultrashort Pulse Laser

The integrated image spectrum and scattering light spectrum of optical emission at normal direction from rear-side of a metallic foil were measured, employing optical CCD camera and OMA optical multi-channel spectrometer. The integrated image spectrum shows that it presents a ring-shape, and in the near margin of the ring-shape a bright localized signal is shown, which is optical transition radiation (OTR) generated by hot electrons transport through solid targets. The scattering spectrum shows that it presents a series of nonperiodic sharp spikes between 300-500 nm, and the sharp spike is ascribed to the coherent transition radiation (CTR) generated by bunches of hot electron beams generated in v x B acceleration mechanism near 400 nm (2 omega). The intensity of transition radiation decreases with the increase of the target thickness.