Nonlinear Thomson scattering from a tightly focused circularly polarized laser with varied incident-pulse durations. (30th December 2020)

• Record Type: Journal Article
• Authors: Wang, Yiqiu; Wang, Conglin; Zhou, Qinyan; Li, Lingxiao; Tian, Youwei
• Is Part Of: Laser physics. Volume 31:Number 1(2021)
• Publication Date: 2020-12-30
• Subjects: nonlinearly Thomson scattering -- circularly polarized Gaussian pulse -- spatial radiation characteristic -- incident pulse duration; Lasers -- Periodicals; 621.36605
• DOI: 10.1088/1555-6611/abd3f7
• Languages: English
• ISSNs: 1054-660X

Abstract

Abstract: In this paper, nonlinear Thomson scattering in an intense ( a 0 = 6 ) tightly focused ( b 0 = 3 μ m ) Gaussian laser pulse is theoretically and numerically investigated to demonstrate varying spatial characteristics in the few-cycle and multi-cycle domains. We find that within ultrashort incident laser pulses, electrons have the potential to radiate a single attosecond pulse with a large signal-to-noise ratio, which turns into a train of attosecond pulses with a multi-cycle laser. Furthermore, a novel asymmetry phenomenon is discovered for the first time in the few-cycle domain whereby spatial radiation lasts for only one circle with apparent peaks and valleys, in contrast to the helical radiation pattern apparent in the multi-cycle domain, which gradually turns into a common fourfold-symmetry pattern. This means that the difference between tightly and non-tightly focused laser pulses can be bridged utilizing an appropriate incident pulse duration under specific conditions. The above difference is demonstrated again in the polar plane, where electrons change from a light-spot to a light-band radiation feature when the incident pulse duration increases.