Polarization-dependent phase-modulation metasurface for vortex beam (de)multiplexing

Abstract

Vortex beams (VBs) carrying orbital angular momentum (OAM) have shown promising potential in enhancing communication capacity through the possession of multiple multiplexing dimensions involving the OAM mode, polarization, and wavelength. Although many research works on multidimensional multiplexing have been conducted, the (de)multiplexer compatible with these dimensions remains elusive. Following the expanded concept of the Pancharatnam–Berry (PB) phase, we designed a polarization-dependent phase-modulation metasurface to phase-modulate the two orthogonal linearly polarized components of light, and two Dammann vortex gratings with orthogonal polarization responses were loaded to simultaneously (de)multiplex OAM mode and polarization channels. As a proof of concept, we constructed a 16-channel multidimensional multiplexing communication system (including two OAM modes, two polarization states, and four wavelengths), and 400 Gbit/s quadrature-phase shift-keying (QPSK) signals were transmitted. The results demonstrate that the OAM mode and polarization channels are successfully (de)multiplexed, and the bit-error-rates (BERs) are below 1.67 × 10−6 at the received power of −15 dBm.

Monolayer Chiral Metasurface for Generation of Arbitrary Cylindrical Vector Beams

“…To solve this problem, we designed two types of chiral unit cells based on the geometric phase-principle for achieving independent modulation on LCP and RCP beams with high modulation efficiency and robustness. The second problem is that in many polarizationmultiplexing structures, the output orthogonal polarization components are not in complete overlap [17][18][19]. Here, we make the output of LCP and RCP holographic beams perfectly overlap in the same position based on the detour-phase principle.…”

“…Based on the geometric-phase principle, two types of chiral unit cells are designed with multiple rectangular nano-slits on a gold film, enabling independent modulation for the left-handed and right-handed circularly polarized (LCP and RCP) parts of the incident linearly polarized beam. The distributions of the two types of unit cells on the gold surface are arranged according to detour-phase principle [17]; thus, two different holographic phases can be loaded onto the LCP and RCP components of transmitted beam, respectively. As a result, CVBs with arbitrary polarized angles and orders, and even more complex vector beams like optical skyrmion, can be generated through the metasurface from a linearly polarized incident beam.…”

Guided‐Wave‐Excited Metasurface with Phase Modulation for Multichannel OAM Vortex Beams Generation and Switching

“…[2,17,18] Significant progress has been made in the realization of OAM vortex beams using a single layer of metasurface, including the successful generation of single OAM vortex beams, [19,20] multi-beam or multi-mode OAM vortex beams, [21][22][23][24] and multi channel OAM vortex beams based on polarization or angle multiplexing. [25][26][27] As the demand for faster communication speeds and increased capacity continues to rise, the integration and versatility of devices become paramount. Consequently, research on multiplexed OAM vortex beams has gained increasing attention.…”

Transmissive Polarization Converter with Eliminated Filtering Effect Based on Non‐Reciprocal Metasurface

“…[19] This filtering effect on 𝜶* accompanying the cross-polarization conversion leads to that the total transmission efficiency toward a specific polarization can not exceed 50% when two polarized orthogonal beams with equal power illuminate on the PCM. Due to the PCMs often serve as the front-end devices for expanding the channel capacity of wireless systems, [15,20,21] the filtering effect may cause the huge adverse impacts on the acquisition of signals, especially for the radar perception and the target detection. Recently, various of reconfigurable PCMs have been proposed by integrating the RF devices, [22][23][24] tunable materials, [25] and mechanical adjustment components.…”