Rigorous theoretical model of single-cycle vortex pulse beams produced by oscillating electric dipole arrays

Abstract

In this paper, we obtain an accurate description of single-cycle vortex pulse beams (SCVPBs) beyond the slowly varying envelope approximation. The SCVPBs are produced by an annular loop composed of oscillating electric dipole arrays. Based on the theoretical model of SCVPBs, simulation results show that the original donut-shaped distribution will evolve into a multi-ring pattern because of the interference effects during transmission. Unlike the π -phase jump effects in different rings in Laguerre–Gauss beams, the spiral isophasal lines of the SCVPBs show continuous change and spatially curved configurations in various donuts which are closely related to the energy distribution of the propagating pulses. In addition, we find the counter-rotating effects of the longitudinal Poynting vector of SCVPBs and calculate the rotation angle. Finally, we discuss the spatiotemporal coupling phenomenon of SCVPBs.