The Optimization Of Extreme Ultraviolet Vortex Beams Based On High-order Harmonic Generation

The development on ultrafast and ultraintense laser pulses has greatly improved the ability to study materials science,life science,chemical reactions,and quantum state evolution of atoms molecules.Optical field manipulation includes multidimensional parameter control such as phase,amplitude,polarization,frequency,and vortex.Light vortex has potential applications in optical communication,micro manipulation,and other fields.In recent years,the development of the vortex beam on short wavelength field has extended from IR to extreme ultraviolet(EUV)and even Xray range.Based on the high-order harmonic generation(HHG),vortex beams can be extended to EUV wavelength,which provides important technical support for the generation of attosecond vortex fields,facilitating precision control at the time scale of electron in atoms.In this paper,we utilized NIR vortex beam to drive and obtain EUV vortex beams through high-order harmonic generation.And the optimization with the multi parameters was conducted.By comparing the harmonic spectra driven by Gaussian and vortex beams or vector beams,it is found that the vortex harmonic spectra have obvious singularities,indicating that HHG transfer properties to the EUV fields.The effects of Gaussian and vortex or vector beams are well studied,including the influence of intensity,focus position,and gas pressure,achieving optimal phase matching and obtaining optimized vortex harmonic fields.This study experimentally obtained vortex and vector beams in the EUV range,which is important and helpful for exploring new mechanisms of interaction between EUV light and atom/molecule.