Tight focusing of femtosecond elliptically polarised vortex light pulses  

作　　者：华黎闽 陈宝算 陈子阳 蒲继雄 

机构地区：[1]College of Information Science and Engineering,Institute of Optics and Photonics,Huaqiao University

出　　处：《Chinese Physics B》2011年第1期358-365,共8页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.60977068);the Natural Science Foundation of Fujian Province,China(Grant No.A0810012);the Open Research Fund of State Key Laboratory of Transient Optics and Photonics,Chinese Academy of Sciences(Grant No.SKLST200912)

摘　　要：This paper studies the tight focusing properties of femtosecond elliptically polarised vortex light pulses. Based on Richards-Wolf vectorial diffraction integral, the expressions for the electric field, the velocity of the femtosecond light pulse and the total angular momentum of focused pluses are derived. The numerical calculations are also given to illustrate the intensity distribution, phase contour, the group velocity variation and the total angular momentum near the focus. It finds that near the focus the femtosecond elliptically polarised vortex light pulse can travel at various group speeds, that is, slower or faster than light speed in vacuum, depending on the numerical aperture of the focusing objective system. Moreover, it also studies the influence of the numerical aperture of the focusing objective and the time duration of the elliptically polarised vortex light pulse on the total angular momentum distribution in the focused field.This paper studies the tight focusing properties of femtosecond elliptically polarised vortex light pulses. Based on Richards-Wolf vectorial diffraction integral, the expressions for the electric field, the velocity of the femtosecond light pulse and the total angular momentum of focused pluses are derived. The numerical calculations are also given to illustrate the intensity distribution, phase contour, the group velocity variation and the total angular momentum near the focus. It finds that near the focus the femtosecond elliptically polarised vortex light pulse can travel at various group speeds, that is, slower or faster than light speed in vacuum, depending on the numerical aperture of the focusing objective system. Moreover, it also studies the influence of the numerical aperture of the focusing objective and the time duration of the elliptically polarised vortex light pulse on the total angular momentum distribution in the focused field.

关 键 词：tight focusing ultrashort oulse ellioticallv oolarised vectorial Debve integral 

分 类 号：O436.3[机械工程—光学工程]