基于XUV激光脉冲和反应显微成像技术的原子分子光物理实验平台

Experimental Platform of Atomic and Molecular Photophysics Based on XUV Laser and Reaction Microscope

基于高次谐波技术的超快激光系统可以通过控制脉冲时序实现对目标量子态的精准操控,反应显微成像谱仪实现了4π立体角内对量子少体碰撞过程的准确测量,两项先进系统的结合将极大拓展量子少体动力学研究的领域。目前,高次谐波的单频选择至关重要,同时反应显微成像谱仪的分辨率受真空度及冷靶分散度的影响较大。中国科学院近代物理研究所通过采用多级差分、钛真空靶室的设计,使得谱仪的真空度达到10^–11 mbar量级,有效降低了本底噪声的影响;升级改造传统超音速冷靶系统的靶束产生装置,实现了靶厚度的自由调控,大大提高了探测器记录事件的准确性;本实验平台结合高次谐波产生多阶XUV脉冲单能化技术,实现了单能XUV超快激光系统和反应显微成像谱仪成功结合,该系统可以产生能量范围在20~100 eV之间的XUV脉冲,能够研究电离能或解离能在100 eV以下的原子分子动力学过程。

Ultrafast laser system based on High Harmonic Generation(HHG)technology can not only accurately make atoms and molecules to the target quantum state,but also control the target quantum state by controlling the pulse time accurately.The reaction microscope can accurately measure the differential cross section in 4πsolid angle in the quantum few-body collision,which greatly improves the measurement accuracy and the efficiency of experimental study on quantum few-body collision dynamics.The combination of these two advanced technologies will greatly expand the field of quantum few-body dynamics.At present,a single frequency selection of HHG is very important,and the resolution of the reaction microscope is mainly affected by the vacuum degree and the dispersion degree of the cold target.The Institute of Modern Physics(IMP)of Chinese Academy of Sciences(CAS)adopts the design of multistage differential system and titanium vacuum target chamber,which makes the vacuum degree of the spectrometer reach 10^–11 mbar.This design greatly reduces the influence of background noise.Moreover,the supersonic cold target system is upgraded to realize the free control of the target thickness,which improves the accuracy of event recorded by the detector.Meanwhile,the XUV ultrafast laser system and the reaction microscope were successfully combined by using the multi-order XUV pulse monochromatic technology of HHG.The XUV pulse energy generated by this experimental platform ranges from 20 to 100 eV,so atomic and molecular dynamics processes with ionization or dissociation energy below 100 eV can be studied.