Time-resolved study of the lasing emission from high vibrational levels of N2^+ pumped with circularly polarized femtosecond pulses  

作　　者：Dongjie Zhou Xiang Zhang Qi Lu Qingqing Liang Yi Liu 周冬杰;张翔;卢琦;梁青青;刘一(Shanghai Key Laboratory of Modern Optical System,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]Shanghai Key Laboratory of Modern Optical System,University of Shanghai for Science and Technology,Shanghai 200093,China

出　　处：《Chinese Optics Letters》2020年第2期70-74,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.11574213 and 11904232);Innovation Program of Shanghai Municipal Education Commission(No.2017-01-07-00-07-E00007);the Shanghai Municipal Science and Technology Commission(No.17060502500);the support of the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning(No.TP2014046).

摘　　要：We experimentally investigated the forward 353.8 nm radiation from plasma filaments in pure nitrogen gas pumped by intense circularly polarized 800 nm femtosecond laser pulses.This emission line corresponds to the B^2Σu^+(u'=4)-X^2Σg^+(u=3)transition of nitrogen ions.In the presence of an external seeding pulse,the 353.8 nm signal was amplified by 3 orders of magnitude.Thanks to the much enhanced intensity,we performed time-resolved measurement of the amplified 353.8 nm emission based on the sum-frequency generation technique.It was revealed that the built-up time and duration of these emissions are both inversely proportional to the gas pressure,while the radiation peak power grows up nearly quadratically with pressure,indicating that the 353.8 nm radiation is of the nature of superradiance.

关 键 词：FEMTOSECOND PULSES plasma nitrogen ions SUPERRADIANCE TIME-RESOLVED measurement 

分 类 号：TN24[电子电信—物理电子学]