title: Generation of elliptically polarized nitrogen ion laser fields using two-color femtosecond laser pulses.
abstract: We experimentally investigate generation of nitrogen molecular ion (N2+) lasers with two femtosecond laser pulses at different wavelengths. The first pulse serves as the pump which ionizes the nitrogen molecules and excites the molecular ions to excited electronic states. The second pulse serves as the probe which leads to stimulated emission from the excited molecular ions. We observe that changing the angle between the polarization directions of the two pulses gives rise to elliptically polarized N2+ laser fields, which is interpreted as a result of strong birefringence of the gain medium near the wavelengths of the N2+ laser.
authors.affiliation: School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.|State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Ziting
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chu
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Xie
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Jinping
authors.initials: J
authors.lastname: Yao
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Guihua
authors.initials: G
authors.lastname: Li
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Qiao
authors.affiliation: School of Physics Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Zhanshan
authors.initials: Z
authors.lastname: Wang
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.|Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Cheng