Generating Different Polarized Multiple Vortex Beams at Different Frequencies from Laminated Meta-Surface Lenses.

Pengfei Gao,Rui Yang

doi:10.3390/mi13010061

Abstract

We demonstrate the generation of multiple orbital angular momentum (OAM) vortex beams with different radiating states at different frequencies through a laminated meta-surface lens consisting of a dual polarized meta-array interconnected with a frequency selective meta-array. The co-linearly polarized (LP) waves from the source can directly penetrate the meta-surface lens to form multiple OAM vortex beams at one frequency. On the other hand, the meta-surface lens will be capable of releasing the cross-LP counterparts at another frequency with high-efficient polarization conversions to have multiple OAM vortex radiations with different radiating directions and vortex modes. Our design, using laminated meta-surface lens to synthesize multiple OAM vortex beams with orthogonal polarizations at different frequencies, should pave the way for building up more advanced vortex beam communication system with expanded diversity of the meta-device.

Highlights

Orbital angular momentum (OAM) vortex beams, with the special intensity distributions and spiral phase fields, have demonstrated great potential to improve the spectral efficiency in the wireless communication [1–7] due to the good orthogonality between different topological charges of the radiating mode
Meta-surfaces have demonstrated the great capacity of polarization conversions [23–28], where linearly polarized (LP) waves are shown to be transformed into their cross counterparts through re-assigning the amplitudes of co- and cross-polarized components
We demonstrate the generation of different polarized multiple vortex beams at different frequencies from laminated meta-surface lenses consisting of dual polarized meta-arrays interconnected with frequency selective meta-arrays

Summary

Introduction

Orbital angular momentum (OAM) vortex beams, with the special intensity distributions and spiral phase fields, have demonstrated great potential to improve the spectral efficiency in the wireless communication [1–7] due to the good orthogonality between different topological charges of the radiating mode. Meta-surfaces have demonstrated the great capacity of polarization conversions [23–28], where linearly polarized (LP) waves are shown to be transformed into their cross counterparts through re-assigning the amplitudes of co- and cross-polarized components Most of these works of literature can solely operate at a single frequency with specific wave modulations as they are composed of single-formed meta-atom array. Hybrid meta-unit arrays forming the dual-band and multiband meta-surfaces are shown to be capable of generating different functionalities at different frequencies It would offer a great way of multiplexing to expand the channel capacity if the polarization states of multiple OAM vortex beams could be prescribed and re-produced using the same generator at different frequencies.

Design and Numerical Results

Findings

Conclusions