Anisotropic coherence induced nonuniform amplification in N_(2)^(+)  

作　　者：Hongqiang Xie Qian Zhang Hongbin Lei Na Wang Yuhan Zheng Zhiming Chen Guihua Li Zengxiu Zhao 

机构地区：[1]School of Science,East China University of Technology,Nanchang 330013,China [2]Department of Physics,National University of Defense Technology,Changsha 410073,China [3]School of Science,East China Jiaotong University,Nanchang 330013,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第12期17-23,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2019YFA0307703);the National Natural Science Foundation of China(Grant Nos.12074063,12064009,12264003,and12264002);the Jiangxi Provincial Natural Science Foundation(Grant Nos.20232ACB211007,20212BAB211008,and 20232BAB201041)。

摘　　要：The continuous progress in N_(2)^(+) lasing recently stimulates a great deal of interest in nonlinear and quantum optics of molecular ions,while a complete description of the ionic polarization is still lacking to date.In this work,we are dedicated to constructing the fundamental ionic polarization theory where several ubiquitous strong-field processes including ionization,electronic couplings and molecular alignment jointly determine the spatial arrangement of ions.With the model,the elusive polarization of N_(2)^(+) lasing can be well interpreted.Our results show that the different electronic transition rules for strong-field ionization and resonant couplings result in peculiar population distributions of various electronic states of N_(2)^(+) in space.Meanwhile,the spatial nonuniformity of population distribution can be aggravated or mitigated during field-free evolutions of coherent molecular rotational wave packets.Furthermore,when a follow-up resonant seed pulse interacts with the prepared ionic system,the anisotropic quantum coherence determining the polarization of subsequent N_(2)^(+) lasing can be established.The qualitative agreement between experiments and simulations confirms the validity of the proposed model.The findings provide critical insights into the polarization and radiation mechanisms of molecular ions constructed via ultrafast laser pulses.

关 键 词：anisotropic coherence air lasing nonuniform amplification 

分 类 号：TN24[电子电信—物理电子学] O56[理学—原子与分子物理]