中国物理B ›› 2011, Vol. 20 ›› Issue (1): 14202-014202.doi: 10.1088/1674-1056/20/1/014202
• CLASSICAL AREAS OF PHENOMENOLOGY • 上一篇 下一篇
华黎闽, 陈宝算, 陈子阳, 蒲继雄
Hua Li-Min(华黎闽),Chen Bao-Suan(陈宝算),Chen Zi-Yang(陈子阳),and Pu Ji-Xiong(蒲继雄)†
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.
中图分类号: (Diffraction and scattering)