In order to investigate the detail propertities of the focal spots for the few-cycle radially polarized femtosecond pulses,the numerical focusing modeling was established,and the intensity and vector distribution of the focal electric field were calculated and simulated.The temporal and spatial properties of the focal electric field are included in the modeling.According to the simulation results,the intensity decreases sharply from the focal center,and the oscillation direction changes periodically.Compared with the CW laser beam with the same power,the pulse possesses smaller focusing spot and higher peak power.Furthermore,by controlling the optical length,the synthetic electric fields in the forward direction are of greater ratio than the backward electric fields for a non-chirp few-cycle radially polarized femtosecond pulses beam,which will be favorable for direct laser-induced electron acceleration.The analysis is significant for designing scheme for electron acceleration with the few-cycle radially polarized femtosecond pulses,and also can be a valuable reference for the ultra-fast microscopic imaging and detection.
Acta Photonica Sinica
The National Natural Science Foundation of China（Nos.61070040,61108089,61205087,61107005 and 51302316）
the Hunan Provincial Natural Science Foundation of China（No.13JJ4003）
the Advanced Research Foundation of National University of Defense Technology（No.JC13-02-09）
Radially polarized light, Few-cycle, Femtosecond pulse, Focusing fields, Electric vector
First author： ZHANG Yuan-da （1989-）, male, postgraduate, M. S. degree, mainly focuses on information optics. Email： zyd04333281256@163. com.
Responsible author（Corresponding author） ： LI Xiu-jian （1974-）, male, associate professor, Ph.D. degree, mainly focuses on information optics, ultrafast optics and optical computing. Email：xjli@nudt. edu. cn