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

Abstract

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 4π solid 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.