45kHz,2kV电光调制电路的设计与应用

根据差分相移量子密钥分发实验对高速电光调制电路的需求,利用固体开关技术和变压器隔离技术,设计出了重复频率为45kHz、输出脉冲电压达到2kV的电光调制电路,该电光调制电路由两部分组成,正负1kV高压脉冲产生电路,其中正1kV高压脉冲的上升沿为50.44ns,下降沿为44.6ns,负1kV高压脉冲下降沿为52.29ns,上升沿为50.44ns。普克尔盒调制电路与光路进行联调,光路的消光比达到23dB,完全满足了消光比为20dB的实验需求。     

Br_2~+分子离子[1+1]双光子解离动力学（英文）

本文利用最近研制的低温离子阱-离子速度成像谱仪在冷离子束中研究了同位素质量分辨的~(79)Br_2~+分子离子的[1+1]双光子激光解离动力学.借助其1~4∑_(u,3/2)~-态为中间态使~(79)Br_2~+共振吸收两个光子至4～5 eV区域的高激发态并发生解离.利用离子速度成像技术获得了光解产物~(79)Br~+的二维速度分布和平动能释放谱.通过平动能释放谱确定了不同解离能量处量子态分辨的解离产物通道分支比.光碎片产物的角分布表明~(79)Br_2~+分子离子的双光子解离是1~4∑_(u,3/2)~-态的△Ω=0平行跃迁至一个Ω=3/2高解离态发生的.由于分子激发态中的强自旋-轨道耦合作用,高激发的四重态很可能参与到实验观测的光解过程.     

Photoelectron angular distributions of H ionization in low energy regime:Comparison between different potentials

We theoretically investigate the low energy part of the photoelectron spectra in the tunneling ionization regime by numerically solving the time-dependent Schrdinger equation for different atomic potentials at various wavelengths.We find that the shift of the first above-threshold ionization(ATI) peak is closely related to the interferences between electron wave packets,which are controlled by the laser field and largely independent of the potential.By gradually changing the short-range potential to the long-range Coulomb potential,we show that the long-range potential's effect is mainly to focus the electrons along the laser's polarization and to generate the spider structure by enhancing the rescattering process with the parent ion.In addition,we find that the intermediate transitions and the Rydberg states have important influences on the number and the shape of the lobes near the threshold.