Realization of polarization evolution on higher-order Poincaré sphere with metasurface

Abstract

We present a simple and convenient method to yield cylindrical vector (CV) beams and realize its polarization evolution on higher-order Poincaré sphere based on inhomogeneous birefringent metasurface. By means of local polarization transformation of the metasurface, it is possible to convert a light beam with homogeneous elliptical polarization into a vector beam with any desired polarization distribution. The Stokes parameters of the output light are measured to verify our scheme, which show well agreement with the theoretical prediction. Our method may provide a convenient way to generate CV beams, which is expected to have potential applications in encoding information and quantum computation.Cylindrical vector (CV) beams are light beams of which the polarization states are arranged with cylindrical symmetry in the beam cross section 1 . A plenty of unique properties originated from their special intrinsic symmetry have distinguished the CV beams from general optical beams with homogeneous polarization. For example, the radially polarized light, a subset of the CV beams, can lead to a strong longitudinal field in the case of strong focusing 2,3 . Because of these particularities, CV beams are expected with a broad applications such as particle trapping 4 , high resolution imaging 2 , particle acceleration 5 , and microscopy 6 .Similar to the geometric representation of homogeneous polarizations on Poincaré sphere, a prominent geometric representation of the CV beams is provided by the so-called higher-order Poincaré sphere (HOPS) 7,8 . In this geometrical representation rule, higher-order Pancharatnam-Berry phase is demonstrated by cyclic transformation of the CV beams on the HOPS 9,10 . This phase is geometric in nature and differs significantly from a dynamic phase, which is proportional to light's total angular momentum. This state evolution will provide an advantage solution to create optical qubits, a single photon carrying several bits of information, which is expected to improve the flexibility of information encoding and simplify quantum computation 11 . Nevertheless, there is still not an effective method to generate all the states on HOPS and realize the state evolution. Most efforts including using subwavelength nanostructure 12-14 , orientation-tailored liquid crystal 15-17 , interferometry 18,19 , laser intracavity devices 20 , and fiber laser 21,22 have been made to obtain the radial and azimuthal polarized beams, however, the other states are seldom referred to.In this work, we demonstrate a simple and convenient method to generate the CV beams and realize the evolution of polarization states on the HOPS. It is well known that the cascaded polarizer, quarter-wave plate (QWP), and halfwave plate (HWP) can generate any elliptical polarization state at will 23 . Furthermore, by modulating the direction of the optical axis of the QWP/HWP, the polarization can evolve along the longitude/latitude on the surface of the fundamental Poincaré sphere. Analogously, while it comes to the CV beams whose pola...

Tailoring optical complex fields with nano-metallic surfaces

“…Recently, an alternative approach to reflection plasmonic metasurfaces has also been presented by replacing metallic plasmonic antennas with their dielectric counterparts, leading to increased efficiency (more than 98%) due to the reduced Ohmic loss [47]. Besides, the dielectric metasurface could also be operated at the transmission mode, a desirable feature for the realization of ultrathin optical elements [48], which have been successfully demonstrated to generate CV beam [49] and CV vortex beam [50]. The dielectric metasurface addresses an increasing need for low-cost and compact optical element without the ohmic loss.…”

Generation of arbitrary cylindrical vector beams on the higher order Poincaré sphere

“…Actually, we can also obtain the cylindrical vector beams and realize their evolution on the HOPS by a metasurface [23], but it is less tunable to achieve a cylindrical vector beam with other topological charges (l ≠ 1) than using the SLM. Here, this can be conveniently achieved by modulating the phase picture displayed on the SLM, and all the theoretical and experimental schemes are applicable in this manipulation.…”

Measuring Orbital Angular Momentum (OAM) States of Vortex Beams with Annular Gratings

“…Until now, a wide variety of methods have been proposed to generate optical vortex beams101112131415. Furthermore, quite a few ways have been presented to measure the topological charge value of vortex beams161718192021222324.…”