In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as m...In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as microscopy and spectroscopy.An experimental study on the HHG driven by vortex and Gaussian beams is conducted in this work.It is found that the intensity of vortex harmonics is positively correlated with the laser energy and gas pressure.The structure and intensity distribution of the vortex harmonics exhibit significant dependence on the relative position between the gas jet and the laser focus.The ring-like structures observed in the vortex harmonics,and the interference of quantum paths provide an explanation for the distinct structural characteristics.Moreover,by adjusting the relative position between the jet and laser focus,it is possible to discern the contributions from different quantum paths.The optimization of the HH vortex field is applicable to the XUV,which opens up a new way for exploiting the potential in optical spin or manipulating electrons by using the photon with tunable orbital angular momentum.展开更多
We experimentally investigated the high-order harmonic generation(HHG)from aligned O_(2) and N_(2) molecules in a linearly polarized laser field,and presented the dependence of the harmonic spectrum on the driving las...We experimentally investigated the high-order harmonic generation(HHG)from aligned O_(2) and N_(2) molecules in a linearly polarized laser field,and presented the dependence of the harmonic spectrum on the driving laser intensity and molecular alignment angle.The minimum position of HHG of O_(2) varies with changing the laser intensity,which is caused by multi-orbital interference.However,the location of the observed minimum structure in N_(2) harmonic spectrum remained unchanged upon changing the laser intensity.The mechanism of the spectral minimum for N_(2) case is regarded as a Cooperlike minimum in HHG associated with the molecular electronic structure.This work indicates that harmonic spectroscopy can effectively uncover information about molecular structure and electron dynamics.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974137,92250306,and 12304302)the National Key Program for Science and Technology Research and Development(Grant No.2019YFA0307700)+1 种基金the Natural Science Foundation of Jilin Province,China(Grant Nos.YDZJ202101ZYTS157 and YDZJ202201ZYTS314)the Scientific Research Foundation of Jilin Provincial Education Department,China(Grant No.JJKH20230283KJ)。
文摘In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as microscopy and spectroscopy.An experimental study on the HHG driven by vortex and Gaussian beams is conducted in this work.It is found that the intensity of vortex harmonics is positively correlated with the laser energy and gas pressure.The structure and intensity distribution of the vortex harmonics exhibit significant dependence on the relative position between the gas jet and the laser focus.The ring-like structures observed in the vortex harmonics,and the interference of quantum paths provide an explanation for the distinct structural characteristics.Moreover,by adjusting the relative position between the jet and laser focus,it is possible to discern the contributions from different quantum paths.The optimization of the HH vortex field is applicable to the XUV,which opens up a new way for exploiting the potential in optical spin or manipulating electrons by using the photon with tunable orbital angular momentum.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.91750104 and 11974137)the Natural Science Foundation of Jilin Province,China(Grant No.YDZJ202101ZYTS157).
文摘We experimentally investigated the high-order harmonic generation(HHG)from aligned O_(2) and N_(2) molecules in a linearly polarized laser field,and presented the dependence of the harmonic spectrum on the driving laser intensity and molecular alignment angle.The minimum position of HHG of O_(2) varies with changing the laser intensity,which is caused by multi-orbital interference.However,the location of the observed minimum structure in N_(2) harmonic spectrum remained unchanged upon changing the laser intensity.The mechanism of the spectral minimum for N_(2) case is regarded as a Cooperlike minimum in HHG associated with the molecular electronic structure.This work indicates that harmonic spectroscopy can effectively uncover information about molecular structure and electron dynamics.
