Arbitrary Linear Polarization Research Articles

Optimized weak measurement model for in-plane and out-of-plane splitting shifts of Photonic Spin Hall effect

The photonic spin Hall effect (PSHE) holds great potential for applications in the fields of precision measurement and sensing. Due to its splitting shift usually at the sub-wavelength level, the current observation and application of PSHE usually rely on weak measurement amplification technology. However, the current optimized weak measurement models are only for the out-of-plane splitting shift of PSHE, and are only applicable to certain specific situations. This greatly limits the application of PSHE in many fields such as precision measurement and sensing, and to some extent hinders the experimental research on PSHE. Based on this issue, by changing the polarization state from 0° or 90° to arbitrary linear polarization incidence, and extending the reflection coefficient from real number to complex number, a set of optimized weak measurement model with wider applicability for both in-plane and out-of-plane splitting shifts of PSHE is established in this article. It is not only applicable to the case where the pre-selection and post-selection states are arbitrary linearly polarized states, but also to the case where the reflection interface is both absorbent medium and non-absorbent medium. In addition, the correctness of this model is demonstrated through comparative verification. This work not only help to conduct more comprehensive and in-depth research on the PSHE and will also further promotes the application and development of PSHE in the fields of precision measurement and high-sensitivity sensing.

Flexible rotation of linear polarization conversion with a frequency selective surface

A high-efficiency transmitted polarization converter based on a frequency selective surface (FSS) is proposed in this paper. The FSS-based polarization converter (FSS-PC) is designed based on receiving-via-transmitting (RVT) structure. The receiving and transmitting antenna structures are interconnected by the transmission line, designed in the form of metallized via holes. For any linearly polarized (LP) electromagnetic wave, our proposed FSS-PC has the capability to convert it into another LP electromagnetic wave. This converted wave will have a counterclockwise rotation angle of 2φ relative to the incident wave at 11 GHz. This is achieved by adjusting the relative azimuth φ between the polarization plane of the incident LP wave's electric field and the converter. Meanwhile, the FSS-PC can achieve exceptionally high polarization conversion above −0.30 dB at the central frequency of 11 GHz. Furthermore, as the azimuth of the incident electric field varies, this high-efficiency polarization conversion capability remains stable. The prototype has been fabricated and measured, and the measured results agree well with the simulated ones, thus confirming the effectiveness of the proposed design.

All-dielectric terahertz metasurfaces for arbitrary linear polarization detection

The polarization state, an intrinsic property of electromagnetic waves, plays a key role in determining the mechanism of light–matter interactions. Recently, the bulky elements for evaluating polarization states have been miniaturized by using metasurfaces. However, determining arbitrary linear polarization (LP) states from vortex beams generated by metasurfaces is quite challenging. Here, a general design of all-silicon quasi-periodic arrays based on polarization multiplexing technology is proposed, which can be used for the detection of arbitrary incident LP state. By embedding independent helical phase profiles in two orthogonal LP channels, the generated interference spot at the predesigned focal plane is resolvable in a proper polarized direction. Benefiting from the establishment of a parametric theoretical model, the evolution of the incident polarization can be determined using key parameters defined on the pixelated focal plane. The proposed method can flexibly determine the polarization state of incident terahertz waves, which has great potential in remote sensing, high-resolution imaging, and data communication.

Modulation approach of arbitrary linear polarization states of optical fields using single-beam coding for next-generation optical storage in glass

Modulation approach of arbitrary linear polarization states of optical fields using single-beam coding for next-generation optical storage in glass

Thickness-dependent in-plane shift of photonic spin Hall effect in an anisotropic medium.

As the in-plane spin splitting (IPSS) has a broad application for the precision measurement and sensing, it is extremely important to explore its enhancement mechanism via the photonic spin Hall effect (PSHE). However, for a multilayer structure, the thickness in most of previous works is generally set as a fixed value, lacking the deeply exploration of the influence of thickness on the IPSS. By contrast, here we demonstrate the comprehensive understanding of thickness-dependent IPSS in a three layered anisotropic structure. As thickness increases, near the Brewster angle, the enhanced in-plane shift exhibits a thickness-dependently periodical modulation, besides with much wider incident angle than that in an isotropic medium. While near the critical angle, it becomes thickness-dependently periodical or linear modulation under different dielectric tensors of the anisotropic medium, no longer keeps almost constant in an isotropic medium. In addition, as exploring the asymmetric in-plane shift with arbitrary linear polarization incidence, the anisotropic medium could bring more obvious and wider range of thickness-dependently periodical asymmetric splitting. Our results deepen the understanding of enhanced IPSS, which is expected to promise a pathway in an anisotropic medium for the spin control and integrated device based on PSHE.

Multiwavelength Achromatic Metalens in Visible by Inverse Design

AbstractAchromatic metalenses are promising alternatives to traditional lenses, allowing the miniaturization of optical systems. However, the limitation due to the group delay range of the meta‐atoms that can be fabricated requires a trade‐off relationship between the working bandwidth, numerical aperture (NA), and aperture of the achromatic metalens operating in a continuous spectrum. Considering that light sources used in most optical systems to illuminate or display images in most optical systems generate multiwavelength light with a narrow bandwidth, an efficient end‐to‐end inverse design framework for multiwavelength achromatic metalenses is implemented. As a proof of concept, an achromatic metalens with an NA of 0.3 and a diameter of 115 µm at four visible wavelengths and arbitrary linear polarization is designed and experimentally demonstrated. The measured results show a maximum focal length shift of 5.2778%. The proposed strategy avoids complicated physical models, enabling the integration of complex functionalities into a single metasurface, thereby driving the design of efficient and emerging devices.

Modular Design for Versatile Broadband Polarizing Metasurfaces with Freely Switching Functions

AbstractPolarization is a fundamental property of electromagnetic waves that plays a key role in many physical phenomena and applications. Schemes to manipulate it are revisited with the emergence of metasurfaces, which have brought multi‐functionalities straightforwardly. However, this has come at the expense of design complexity that relies strongly on field theory. Here, an ingenious strategy of modular design is proposed to construct subwavelength multifunctional polarization control devices. Chiral metasurfaces with different handedness are first proposed and regarded as modules. The versatile polarization controller can thus be obtained with the combination of different modules. These experiments demonstrate that the well‐designed polarization controller possesses reconfigurable functionality, and various broadband polarization and amplitude regulation functions with high efficiency including arbitrary linear polarization rotation, asymmetric transmission effect, neutral‐density‐like filter, polarization beam splitter, etc., can be readily realized just by changing the cascaded modules. The physical mechanisms of the versatile polarization controller and chiral metasurface modules are both guaranteed by the Fabry–Pérot‐like resonances, which are theoretically verified via the transfer matrix method. It is envisioned that the modular concept will be of great benefit to designing compact multifunctional polarization controllers.

Generation of vector beams based on diffraction characteristics of a linear polarization hologram in coaxial recording.

Polarization holography is an effective tool for realizing light field manipulation and can be utilized to generate vector beams. Based on the diffraction characteristics of a linear polarization hologram in coaxial recording, an approach for generating arbitrary vector beams is proposed. Unlike the previous methods for generating vector beams, in this work, it is independent of faithful reconstruction effect and the arbitrary linear polarization waves can be used as reading waves. The desired generalized vector beam polarization patterns can be adjusted by changing the polarized direction angle of the reading wave. Therefore, it is more flexible than the previously reported methods in generating vector beams. The experimental results are consistent with the theoretical prediction.

Effect of the incident polarization on in-plane and out-of-plane spin splitting near the critical angle.

To reveal the effect of the incident polarization on the spin splitting of the photonic spin Hall effect (that is, the spatial and angular in-plane and out-of-plane spin splitting), we systematically study the phenomena and characteristics of these four spin splitting generated when the beam with arbitrary linear polarization is reflected from the non-absorbing medium interface and the absorbing medium interface. Several features of the relationship between the incident polarization and the four kinds of spin splitting are found. In addition, It is also found that the in-plane angular and spatial shifts are significantly enhanced near the critical angle, even reaching their theoretical upper limit. However, the out-of-plane shifts are not enhanced. The research in this paper will contribute to a deeper understanding of PSHE. These findings can also provide new ideas and methods for precision metrology, photonic manipulation, and photonic device fabrication.

Adding/dropping polarization multiplexed cylindrical vector beams with local polarization-matched plasmonic metasurface.

Here we propose a polarization-dependent gradient phase modulation strategy and fabricate a local polarization-matched metasurface to add/drop polarization multiplexed cylindrical vector beams (CVBs). The two orthogonal linear polarization states in CVB multiplexing will represent as radial- and azimuthal-polarized CVBs, which means that we must introduce independent wave vectors to them for adding/dropping the polarization channels. By designing the rotation angle and geometric sizes of a meta-atom, a local polarization-matched propagation phase plasmonic metasurface is constructed, and the polarization-dependent gradient phases were loaded to perform this operation. As a proof of concept, the polarization multiplexed CVBs, carrying 150-Gbit/s quadrature phase shift keying signals, are successfully added and dropped, and the bit error rates approach 1 × 10-6. In addition to representing a route for adding/dropping polarization multiplexed CVBs, other functional phase modulation of arbitrary orthogonal linear polarization bases is expected, which might find potential applications in polarization encryption imaging, spatial polarization shaping, etc.

Dynamic Phase and Polarization Modulation Using Two-Beam Parallel Coding for Optical Storage in Transparent Materials.

In this paper, we propose and experimentally demonstrate a parallel coding and two-beam combining approach for the simultaneous implementation of dynamically generating holographic patterns at their arbitrary linear polarization states. Two orthogonal input beams are parallelly and independently encoded with the same target image information but there is different amplitude information by using two-phase computer-generated holograms (CGH) on two Liquid-Crystal-on-Silicon-Spatial-Light Modulators (LCOS SLMs). Two modulated beams are then considered as two polarization components and are spatially superposed to form the target polarization state. The final linear vector beam is created by the spatial superposition of the two base beams, capable of controlling the vector angle through the phase depth of the phase-only CGHs. Meanwhile, the combined holographic patterns can be freely encoded by the holograms of two vector components. Thus, this allows us to tailor the optical fields endowed with arbitrary holographic patterns and the linear polarization states at the same time. This method provides a more promising approach for laser data writing generation systems in the next-generation optical data storage technology in transparent materials.

Pattern and polarization reconfigurable loop antenna with circular high‐impedance surface for 5G micro base station application

A novel type of loop antenna backed by four-element circular high-impedance surface (CHIS) for 5G micro base station application is presented. The CHIS is composed of four elements, each one in the shape of a truncated sector, and the complete CHIS acts as the reflection plane for the main radiating loop placed above. In all, the proposed antenna structure contains three variations, the size of which are all less than π × 322 × 7 mm3. By properly adjusting the distribution of excitations, the first antenna can steer its beam to all four quadrants with a tilted angle of θ = 15°, and the remaining two antennas are capable of changing its polarization state among arbitrary linear polarization, left-handed circular polarization and right-handed circular polarization. Particularly, the second four-port antenna can also achieve pattern reconfiguration by steering its beam tilting towards four different quadrants, covering the space of −30° ≤ θ ≤ 30° with realized gain over 7.19 dBi. To validate the proposed concept, three antenna prototypes operating at 3.5 GHz are designed, fabricated and measured. The measured results agree well with the simulated ones, proving that the proposed antenna can achieve the desired reconfiguration.

Ultra-broadband Pancharatnam-Berry phase metasurface for arbitrary rotation of linear polarization and beam splitter.

A systematic study of a robust angular tolerance ultra-broadband metasurface for arbitrary rotation of linear polarization is demonstrated. The proposed method combines the spin-dependent Pancharatnam-Berry phase and the generalized Snell's law to achieve an arbitrary angle linear polarization rotator and beam splitter. Numerical results of one terahertz example show that a 90° polarization rotator has a polarization conversion ratio of more than 90% from 1.3 to 2.3 THz in the ultra-broadband range. This method represents a significant advance in versatile, flexible design and performance compared to previously reported birefringent material wave plates, grating structures, and multi-resonance-based polarization rotators.

Optimal weak measurement in the photonic spin Hall effect for arbitrary linear polarization incidence

The photonic spin Hall effect (SHE) has great potential in precision metrology due to its unique spin modulation characteristics. To improve its potential, the effective enhancement of detection precision has become an important issue. In this work, we theoretically and experimentally demonstrate the optimal weak measurement (optimal overlap of pre-selected and post-selected states) with arbitrary linear polarization incidence for both amplified transverse and in-plane shift. Also, based on photonic SHE, a method for arbitrary linear polarization angle detection is then proposed experimentally with a detection accuracy of 0.04 degree. It can provide a guidance for the weak measurement and enlarge the potential application of photonic SHE in field of precision measurement.

Independent Wavefront Tailoring in Full Polarization Channels by Helicity‐Decoupled Metasurface

AbstractControlling the polarization and wavefront of light is essential for compact photonic systems in modern science and technology. This may be achieved by metasurfaces, a new platform that has radically changed the way people engineer wave–matter interactions. However, it still remains very challenging to generate versatile beams with independent wavefronts in each polarization channel by a single ultrathin metasurface. By modulating both the geometric and propagation phases of the metasurface, here a method is proposed that can generate an assembly of circularly and linearly polarized beams with simultaneously the capability of independent encoding desired wavefront to each individual polarization channel, which is believed to greatly enhance the information capacities of the metadevices. Two proof‐of‐concept designs are experimentally demonstrated in microwave region. Upon the excitation of an arbitrary linear polarization, the first device can generate distinct vortex beams with the desired two linear and two circular orthogonal polarizations, whereas the second one can generate multifoci containing components of full polarizations. This approach to generate versatile polarizations with tailored wavefront may pave a way to achieve advanced, flat, and multifunctional metadevice for integrated systems.

Scalar vortex beam produced through faithful reconstruction of polarization holography

Vortex beams have been widely analyzed and applied in various fields owing to their unique phase and intensity distribution, along with their orbital angular momentum; they can be produced through various methods. This study proposes a method based on polarization holography, contrary to the traditional method of producing vortex beams. This method is significant in that the signal wave in the recording stage is not the generated vortex beam; the reconstructed wave is the vortex beam obtained in the reconstruction stage, which varies from the vortex beams produced by holography, where the signal wave is already a vortex beam. Faithful reconstruction of polarization holography is applied in the experiment, where phenanthrenequinone-doped polymethyl methacrylate (PQ/PMMA) photopolymers are used as the recording material. Scalar vortex beams with arbitrary linear polarization and topological charges can be produced by changing the experimental parameters. The experimental results are satisfactory. Additionally, this work demonstrates the application of polarization holography in light field manipulation. This proposed method has potential applications in optical micro-manipulation and optical tweezers.

The effect of Rayleigh length of incident Gaussian beam on the in-plane angular spin splitting

In this paper, we established the relationship model between Rayleigh length of incident Gaussian beam and in-plane angular spin splitting (IPASS) under arbitrary linear polarization, and systematically investigated the effect of Rayleigh length on the IPASS. The results show that the IPASS shifts decrease with the increase of Rayleigh length, and the smaller the Rayleigh length, the greater its impact on IPASS. The maximum IPASS shift can almost reach half of the beam divergence angle by adjusting incident angle and polarization angle. In addition, several interesting characters of IPASS are discovered.

Generation of a vector light field based on polarization holography.

We propose a simple and effective method for generating a vector light field based on the faithful reconstruction (FR) effect of polarization holography, where the arbitrary linear polarization waves can be faithfully reconstructed by the polarization-sensitive recording media. The scheme incorporates the tunable and switchable dynamics exposure system to manufacture vector beams. By regulating the velocity and the initial polarization through the angle-aperture and the half-wave plate in the dynamics exposure system, the generated optical element can convert a linear polarization wave into a vector beam. We have analyzed the feasibility in theory and demonstrated the generation of the vector beams experimentally which shows good agreement with the theoretical simulations.

Polarization-induced topological phase transition in zigzag chains composed of metal nanoparticles

We theoretically study the topological optical properties in one-dimensional zigzag chains composed of metal nanoparticles. The topological phase transition in the system is realized by controlling the polarization of the external optical field, which is feasible in experiments in contrast with changing the structural parameters. The dipole responses of the system with different bond angles to the external field of arbitrary linear polarization are calculated. It is found that a wide domain of polarization angles is available for a given zigzag chain to observe the polarization-induced topological transition. Different topological phases in the system are checked, which further proves the effectiveness of polarization modulation. The system, an easily implemented platform to study phenomena in topological photonics, might have novel applications in nanoscale optical devices.

Radiation‐Type Metasurfaces for Advanced Electromagnetic Manipulation

AbstractManipulating the phase, polarization, and energy distribution of electromagnetic (EM) waves has facilitated numerous applications. Nowadays, metasurface provides an innovational scenario to carry out more promising and advanced control of EM waves. However, it is a great challenge to manipulate polarization, phase, and energy distribution simultaneously with a low profile. Herein, a class of single‐layer radiation‐type metasurfaces to achieve advanced EM manipulation is proposed. Desired EM functions can be achieved based on the geometric phase and resonant phase. Such metasurfaces enable the capability to manipulate arbitrary phases and linear polarization states simultaneously. Moreover, arbitrary energy distributions can be controlled. As examples of potential applications, three advanced EM functional devices are presented: a novel multiple‐input multiple‐output antenna with efficient crosstalk suppression and information encryption, an energy‐controllable router, and a metasurface holographic imaging based on power transmission algorithm, respectively. The proposed strategy may open up an alternative way of controlling EM waves with advanced performance and minimalist complexity. Moreover, it may lead to advances in information encoding and cryptography.