实验测量了神光 -III原型装置上脉冲强激光与金属靶相互作用产生的电脉冲辐射, 电脉冲峰值梯度为 3 kV/m, 频谱范围大约在 50 MHz～2 GHz, 在 160 MHz等处有明显的特征峰, 信号持续时间大约 60 ns。本文研究表明电偶极辐射是打靶过程产生电磁脉冲信号的来源之一, 由理论模型计算得到频率为 160 MHz的特征峰, 并计算出探测点电场脉冲峰值梯度约为 2 kV/m, 辐射总功率约 105 W, 能量转换率约 10-6, 辐射功率近似正比于激光能量的 4/3次方, 可见激光能量越大, 功率密度越高, 电脉冲的辐射强度越大。大型激光装置上的激光与靶作用产生的电磁脉冲测量, 对大型激光装置产生的电磁辐射的防护有重要指导作用, 在等离子体诊断等领域也有潜在应用价值。

对触发开关和主开关产生电磁辐射的机理进行了详细的分析, 将气体开关导电通道等效为电偶极子, 理论分析了其辐射电磁波的空间分布, 以同轴电缆为实验对象, 研究了电磁辐射的干扰。实验测量了触发开关和主开关的电磁辐射信号, 结果表明, 运用偶极辐射等效可以很好地描述二者的辐射特性。在强流电子束加速器产生电磁辐射的时刻, 同轴电缆中感应出了一定强度的电流, 幅值达3 V, 已经足以对其他信号的准确测量产生影响。

原子与激光场相互作用产生的自发辐射可以用经典电偶极辐射理论很好的描述。通过改变与Sr原子束相互作用激光的偏振方向,分析探测Sr原子束荧光强度的变化,测定了在远场区的电偶极辐射特性。Sr原子电偶极子在远场区辐射能量的空间方向分布满足sin2θ关系,利用这一规律可以有效地探测到最强的荧光光谱。

Light emitted by an atomic source of radiation appears to travel along a straight line (ray) from the location of the source to the observer in the far field. However, when the energy flow pattern of the radiation is resolved with an accuracy better than an optical wavelength, it turns out that the field lines are usually curved. We consider electric dipole radiation, a prime example of which is the radiation emitted by an atom during an electronic transition, and we show that the field lines of energy flow are in general curves. Near the location of the dipole, the field lines exhibit a vortex structure, and in the far field they approach a straight line. The spatial extension of the vortex in the optical near field is of nanoscale dimension. Due to the rotation of the field lines near the source, the asymptotic limit of a field line is not exactly in the radially outward direction and as a consequence, the image in the far field is slightly shifted. This sub-wavelength displacement of the image of the source should be amenable to experimental observation with contemporary nanoscale-precision techniques.

研究了超短光脉冲在GaAs表面激发相干亚毫米波振幅随入射角变化的规律,前后向辐射比值随入射角度变化的规律,实验测量了在GaAs表面镀上极薄金属薄膜后所产生的相干亚毫米波振幅对薄膜厚度的依赖关系;利用光生载流子偶极辐射的理论模型成功地解释了实验得到的角度依赖关系和相干亚毫米波的偏振特性。