Manipulation of plasmonic vortex fields using positive elliptically polarized beams

Several studies have investigated methods for the direct excitation of surface plasmon polariton (SPP) vortex fields by using scalar beams with linear and circular polarization. In this paper, we propose novel devices for generating SPP vortex fields by using positive elliptically polarized beams. These devices excited SPP vortices with a uniform electric field intensity distribution, that did not vary arbitrarily with changes in the incident beam amplitude ratio. Moreover, when the incident scalar beam was transformed into a vector beam with different amplitude ratios at every point in space, the topological charge of the SPP vortex field could be dynamically modulated by changing the polarization order and rotation direction of the incident vector beam. The fields generated by different structures after the superposition of SPP vortices had spatial intensity distributions that varied with changes in the incident beam amplitude ratio. These properties provide a new idea for realizing different spatial intensity distributions for a dynamic modulation SPP field.