Optical free induction decay emission carrying orbit angular momentum from ionic nitrogen enabled by multiple-photon resonance  

作　　者：Kailu Wang Haicheng Mei Jingsong Gao Liang Xu Hongbing Jiang Yi Liu 王凯璐;梅海城;高靖松;许亮;蒋红兵;刘一(Shanghai Key Laboratory of Modern Optical System,University of Shanghai for Science and Technology,Shanghai 200093,China;State Key Laboratory for Mesoscopic Physics,School of Physics,Peking University,Beijing 100871,China;CAS Center for Excellence in Ultra-intense Laser Science,Shanghai 201800,China)

机构地区：[1]Shanghai Key Laboratory of Modern Optical System,University of Shanghai for Science and Technology,Shanghai 200093,China [2]State Key Laboratory for Mesoscopic Physics,School of Physics,Peking University,Beijing 100871,China [3]CAS Center for Excellence in Ultra-intense Laser Science,Shanghai 201800,China

出　　处：《Chinese Optics Letters》2024年第6期177-181,共5页中国光学快报（英文版）

基　　金：supported in part by the National Natural Science Foundation of China (Nos.12034013 and 12204308);the Shanghai Science and Technology Commission (No.22ZR1444100)。

摘　　要：Coherent optical emission of free induction decay (FID) excited by the multiple-photon resonance has been recently observed in nitrogen ions produced by intense femtosecond laser pulses.Here we report that orbit angular momentum (OAM) of the pump laser pulses can be transferred to the much longer pulsed free induction decay emission with the OAM conserved.It was found that when the pump laser frequency approaches the fraction of the 391.4 nm emission (ν_(0)/5),an FID emission is emitted whereas its topological charge was identified to be 5 times of the pump laser.Due to the reduced laser intensity with a vortex pump compared to the conventional Gaussian beam,the resonant pump laser wavelength presents a redshift,and the FID signal is significantly weaker.

关 键 词：air lasing orbital angular momentum free induction decay femtosecond pulses PHOTOIONIZATION 

分 类 号：O437[机械工程—光学工程]