Arbitrary Polarization Research Articles

Loss-less passive polarization rectifier design with minimal etendue and size increase

We describe an approach allowing the passive rectification of the polarization of light with approximately the same beam size, minimal increase of the etendue of the beam and with negligible reduction of its power. This is done for arbitrary (including chaotic) input polarization states and without their prior identification. The tradeoff is the partial increase of the angular spectrum of light. Theoretical estimations are provided along with some preliminary experimental results describing the possible use of this approach with large diameter beams as well as in optical fibers.

Natural frequency analysis of laminated piezoelectric beams with arbitrary polarization directions

Natural frequency analysis of laminated piezoelectric beams with arbitrary polarization directions

Realizing linear-polarization-decoupled quasi-perfect absorption through mirror-symmetric QR-code metasurfaces.

Metamaterial absorbers (MAs) with irregular structures facilitate the attainment of unique absorption properties, leveraging the extensive geometric freedom. However, a challenge arises from the fact that polarization-dependent spectra do not coincide with cross-polarization. In this study, we introduce a MA featuring a mirror-symmetric quick response (QR)-code structure to achieve linear-polarization-decoupled absorption characteristics. We employ a direct binary search algorithm to reverse design the MA structure by specifying absorptivity for eigen-polarization states. Moreover, the absorptivity for arbitrary polarizations can be predicted through linear superposition of the two eigen-polarization states, opening up avenues for investigating polarization-controlled metasurfaces and metamaterials.

Efficient Computation of Overlap Reduction Functions for Pulsar Timing Arrays.

Pulsar timing arrays seek and study gravitational waves (GWs) through the angular two-point correlation function of timing residuals they induce in pulsars. The two-point correlation function induced by the standard transverse-traceless GWs is the famous Hellings-Downs curve, a function only of the angle between the two pulsars. Additional polarization modes (vector or scalar) that may arise in alternative-gravity theories have different angular correlation functions. Furthermore, anisotropy, linear, or circular polarization in the stochastic GW background gives rise to additional structure in the two-point correlation function that cannot be written simply in terms of the angular separation of the two pulsars. In this Letter, we provide a simple formula for the most general two-point correlation function-or overlap reduction function (ORF)-for a gravitational-wave background with an arbitrary polarization state, possibly containing anisotropies in its intensity and polarization (linear and/or circular). We provide specific expressions for the ORFs sourced by the general-relativistic transverse-traceless GW modes as well as vector (or spin-1) modes that may arise in alternative-gravity theories.

Magnetically tunable bound states in the continuum with arbitrary polarization and intrinsic chirality

Magnetically tunable bound states in the continuum with arbitrary polarization and intrinsic chirality

Kinetic theory of vacuum pair production in uniform electric fields revisited

We investigate the phenomenon of electron-positron pair production from vacuum in the presence of a uniform time-dependent electric field of arbitrary polarization. Taking into account the interaction with the external classical background in a nonperturbative manner, we quantize the electron-positron field and derive a system of ten quantum kinetic equations (QKEs) showing that the previously-used QKEs are incorrect once the external field rotates in space. We employ then the Wigner-function formalism of the field quantization and establish a direct connection between the Dirac-Heisenberg-Wigner (DHW) approach to investigating the vacuum pair-production process and the QKEs. We provide a self-contained description of the two theoretical frameworks rigorously proving their equivalence and present an exact one-to-one correspondence between the kinetic functions involved within the two techniques. Special focus is placed on the analysis of the spin effects in the final particle distributions. Published by the American Physical Society 2024

Theoretical analysis of a refractive index sensor based on optical Tamm state of graphene metastructure under arbitrary polarization deflection angle

In this paper, a refractive index sensor based on a metastructure (MS) is proposed, which achieves sensing through the sharp valleys formed in the reflection spectrum by the excitation of optical Tamm states (OTS) by gyroidal graphene. Differences in the refractive index of the filling medium in the pores of gyroidal graphene will cause shifts in the reflection valleys. The graphene layer is followed by a periodic structure consisting of alternating zirconium dioxide (ZrO2) and α-molybdenum trioxide (α-MoO3). The 4 × 4 transfer matrix method (TMM) is used for the calculation of the results, which allows the case of arbitrary polarization deflection angles ϕ to be considered in the discussion. Different values of ϕ can lead to a switch in the dominance of the sensor, specifically, the structure has a larger linear interval but lower sensitivity at ϕ = 0°, which is the opposite of the situation at ϕ = 90°. The sensor can be used in a variety of scenarios such as biochemical sensing, gas detection, etc, and brings the polarization deflection angle of the incident wave into the discussion.

High-accuracy direction measurement and high-resolution computational spectral reconstruction based on photonic crystal array

Portable and wearable miniaturized spectrometers play a crucial role in various fields. In this paper, we present a method for simultaneously realizing high-accuracy direction measurement and high-resolution computational spectral reconstruction based on the angle sensitivity of conventional photonic crystals (PCs), wherein an optical filter array is composed of multiple one-dimensional PCs. The high-angle sensitivity of PCs results in angle-dependent optical spectra. When these spectra with different angles are used to reconstruct the target spectra in an unknown direction and the interval between adjacent angles is sufficiently small, the accurate direction of the target can be automatically identified. Moreover, the computational spectra still have high resolution over a wide range of incidences. The computational spectra under arbitrary polarizations can also be recognized based on the polarization dependence of the PCs at an oblique incidence. Our research results are significant for engineering a new miniaturized comprehensive computational spectrometer with target-direction perception and omnidirectional spectral reconstruction abilities.

Polarization-independent quasi-BIC supported by non-rotationally symmetric dimer metasurfaces.

Asymmetric metasurfaces supporting quasi-bound states in the continuum (-BICs) have recently attracted significant interest in the field of nanophotonics due to their high quality factor and strong light-matter interaction properties. However, asymmetric metasurface structures are susceptible to the polarization state of the incident light, which constrains their potential applications. In this Letter, we present a new, to our knowledge, scheme of polarization-independent quasi-BIC resonance supported by a non-rotationally symmetric nanorod dimer metasurface. By tuning the asymmetry parameter, the designed metasurface exhibits a consistent quasi-BIC response for incident plane waves of arbitrary polarization. The physical mechanism of the quasi-BIC resonance is elucidated by the study of the far-field multipole decomposition and the near-field electromagnetic distribution. We then point out that the realization of the polarization-independent quasi-BIC resonance depends on the transition between magnetic and electric quadrupoles. Furthermore, the designed metasurface is demonstrated to have excellent refractive index sensing performance. This work provides a new idea for the design of polarization-independent and high-performance resonators.

Deterministic and multiuser quantum teleportation network of continuous-variable polarization states

Quantum teleportation is widely applied as a key ingredient in quantum information science, and quantum network provides unique abilities for upscaling its applications. Polarization state of light is a vital degree of freedom with the advantages of remote transfer and direct light-atom interaction. To construct a multiuser quantum network, deterministic quantum teleportation of polarization state in more users' network remains challenging. Compared with photonic quantum state, the deterministic quantum teleportation network of polarization state is realized with a single set of continuous-variable entangled states. The key techniques include only one set of quadrature entangled network, single quadrature controller, and active polarization controller. Arbitrary polarization state is deterministically and controllably teleported in such a system involving four or three users. This system is deterministic and scalable with user number, which enables the potential application in deterministic metropolitan quantum network. Published by the American Physical Society 2024

Directionally Asymmetric in Orbital Angular Momentum Generation Using Single‐Layer Dielectric Janus Metasurfaces

AbstractJanus metasurfaces, offering versatile light manipulation contingent on incident direction, are explored across microwave to mid‐infrared spectra. Nonetheless, prior designs often resort to spatial multiplexing or vertical stacking, entailing complex fabrication. Metallic Janus metasurfaces, owing to material properties, suffer notable Ohmic losses in the visible spectrum. In this study, Single‐layer TiO2‐based Janus metasurfaces with arbitrary polarization control is experimentally demonstrated, exhibiting directionally asymmetric functionalities in spin and orbital angular momentum (OAM). A novel Jones matrix formulation tailored for Janus metasurfaces is presented, enabling efficient generation of two asymmetric, high‐purity OAM states of vortex beams at wavelength of 532 nm, contingent on incidence direction. This innovation facilitates compact and versatile phase manipulation, encompassing applications such as lasers and optical combiners, thereby expanding its utility across diverse domains.

Local control of polarization and geometric phase in thermal metasurfaces.

Thermal emission from a hot body is inherently challenging to control due to its incoherent nature. Recent advances have shown that patterned surfaces can transform thermal emission into partially coherent beams with tailored directionality and frequency selectivity. Here we experimentally demonstrate polarization-selective, unidirectional and narrowband thermal emission using single-layer metasurfaces. By implementing polarization gradients across the surface, we unveil a generalization of the photonic Rashba effect from circular polarizations to any pair of orthogonal polarizations and apply it to thermal emission. Leveraging pointwise specification of arbitrary elliptical polarization, we implement a thermal geometric phase and leverage it to prove previous theoretical predictions that asymmetric chiral emission is possible without violating reciprocity. This general platform can be extended to other frequency regimes in efforts to compactify metasurface optics technologies without the need for external coherent sources.

Tailoring an arbitrary large vectorial structured light beam array utilizing the tensor theory of multiplexed polarization holograms

Vectorial structured light beams, characterized by their topological charge and non-uniform polarization distribution, are highly promising beam modes for several applications in different domains of optics and photonics. To harness its potential specifically in optical communication, data encryption, and optical trapping, it is necessary to tailor a multitude of these beams with arbitrary and large topological charge and polarization distribution. However, achieving the above-mentioned requires bulky optical setups that necessitate the superposition of two beams or involve complex material fabrication techniques that can directly generate these beams. In this paper, we report the generation of a large structured light beam array by utilizing multiplexed polarization holograms, computer-generated holography, and azo-carbazole polymer film. We have developed a theoretical framework for double-exposure polarization holography that enables the possibility of tailoring such a vectorial light beam array. Utilizing the developed theory, we showcase the experimental generation of a structured vector beam array of size 8 × 8 with arbitrary topological charges and polarization distribution in 3 mm × 3 mm area of the polymer film. Exploiting the large space bandwidth of the polymer film, we also demonstrate the generation of vector vortex beam arrays with exceptionally large topological charges (l=100). All the above has been experimentally realized by simply illuminating the hologram with a plane Gaussian beam, and no additional optics are needed. This reported method offers huge potential and opens up new possibilities for the utilization of vectorial structured light beams.

Demonstration of full polarization control of soft X-ray pulses with Apple X undulators at SwissFEL using recoil ion momentum spectroscopy.

The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, the demand for polarization control in X-ray free-electron lasers is increasing to enable polarization-sensitive dynamical studies on ultrafast time scales. The soft X-ray branch Athos of SwissFEL was designed with the aim of providing freely adjustable and arbitrary polarization by building its undulator solely from modules of the novel Apple X type. In this paper, the magnetic model of the linear inclined and circular Apple X polarization schemes are studied. The polarization is characterized by measuring the angular electron emission distributions of helium for various polarizations using cold target recoil ion momentum spectroscopy. The generation of fully linear polarized light of arbitrary angle, as well as elliptical polarizations of varying degree, are demonstrated.

The Design of a Multifunctional Coding Transmitarray with Independent Manipulation of the Polarization States.

Manipulating orthogonally polarized waves independently in a single metasurface is pivotal. However, independently controlling the phase shifts of orthogonally polarized waves is difficult, especially in the same frequency bands. Here, we propose a receiver-phase shift-transmitter transmitarray with independent control of arbitrary polarization states in the same frequency bands, in which transmission rates reach more than 90% in the frequency bands 4.2~4.9 GHz and 5.3~5.5 GHz. By introducing a phase-regulation structure to each element, phases covering 360° for different polarized incident waves can be independently controlled by different geometric parameters, and two-bit coding phases can be obtained. The design principle based on the two-port network's scattering matrix has been analyzed. To verify the independent tuning abilities of the proposed transmitarray for different polarization incidences in the same frequency bands, a multifunctional receive-phase shift-radiation coding transmitarray (RPRCT), which is composed of 16×16 elements, with functions of anomalous refraction (for example, orbital angular momentum wave) and focusing transmission for different polarized incident waves was simulated and measured. The measured results agree reasonably well with the simulated ones. Our findings provide a simple method for obtaining a multifunctional metasurface with orthogonal polarization in the same frequency bands, which greatly improves the capacity and spectral efficiency of communication channels.

Reaching the efficiency limit of arbitrary polarization transformation with non-orthogonal metasurfaces

Polarization transformation is at the foundation of modern applications in photonics and quantum optics. Notwithstanding their applicative interests, basic theoretical and experimental efforts are still needed to exploit the full potential of polarization optics. Here, we reveal that the coherent superposition of two non-orthogonal eigen-states of Jones matrix can improve drastically the efficiency of arbitrary polarization transformation with respect to classical orthogonal polarization optics. By exploiting metasurface with stacking and twisted configuration, we have implemented a powerful configuration, termed “non-orthogonal metasurfaces”, and have experimentally demonstrated arbitrary input-output polarization modulation reaching nearly 100% transmission efficiency in a broadband and angle-insensitive manner. Additionally, we have proposed a routing methodology to project independent phase holograms with quadruplex circular polarization components. Our results outline a powerful paradigm to achieve extremely efficient polarization optics, and polarization multiplexing for communication and information encryption at microwave and optical frequencies.

Chip‐Scale Optically Pumped Magnetometry Enabled by Tailorable Elliptical Dichroism Metasurface

AbstractEmerging miniaturized optically pumped magnetometers (OPMs) are becoming one of the most desirable approaches for biomagnetic imaging, especially for OPM with elliptically polarized light, which promises single‐light optical pumping and detection with high sensitivity. However, conventional schemes of this kind require a set of bulk polarization optics and tedious adjustment procedures, which compromise the system's compactness and practicality. In this paper, a novel chip‐scale OPM scheme that leverages the monolithic elliptical meta‐polarizer is presented and experimentally demonstrated. The meta‐polarizer with a side length of 3 mm is laid out on a 2 × 2 cm2 glass wafer. It offers the capability to convert arbitrary incident polarization into the desired elliptical polarization and exhibits a tailorable elliptical dichroism (ED) of ≈0.77 at the wavelength of 795 nm. A 4 × 4 × 4 mm3 vapor cell containing 87Rb and N2 is combined with this elliptical meta‐polarizer to construct a miniaturized OPM. The sensitivity of this sensor reaches approximately 13 fT/Hz1/2 in a four‐layer magnetic shield with a dynamic range near zero magnetic field ≈ ±0.55 nT. By exploiting the advantages of planar integrated optics, reduced footprints and scalability are promised. And this work paves the way for the integration of emerging quantum sensors on a chip.

Dynamic control of polarization conversion based on borophene nanostructures in optical communication bands

Polarized light has a number of potential applications in the communication bands, including optical communication, polarization imaging, quantum emission, and quantum communication. Nonetheless, there is a need to enhance the dynamic tunability, broadband operation, and flexibility of polarization control. Here, a borophene structure is proposed to dynamically control the polarization state of reflected light. The coherent excitation of localized surface plasmons (LSPs) empowers the achievement of a perfect linearly-circularly polarization conversion at the commercially important communication wavelength of 1550 nm. The dynamic tunability and switching, as well as the arbitrary polarization conversion, are enabled over a wide spectral range by modulating the carrier concentration of borophene. Moreover, by deforming the borophene array and alternately stimulating the upper and lower layers of the LSPs mode, the polarization rotation direction can be flexibly switched. Finally, the process of near-field coupling between the LSPs and dipole light source positioned at a chosen hotspot is demonstrated. This coupling enables polarization-tunable spontaneous emission enhancement, with a spontaneous emission enhancement exceeding 900. The proposed design contributes to enhancing the speed and efficiency of communication within the domain of quantum communication.

Generating Arbitrary Shaped Near-Field With Arbitrary Polarization by Combining Tensor Holographic Impedance Metasurface and Phase Conjugation Techniques

Generating Arbitrary Shaped Near-Field With Arbitrary Polarization by Combining Tensor Holographic Impedance Metasurface and Phase Conjugation Techniques

Optimal Synthesis of Array Focused Power Pattern With Arbitrary Polarization and Low Sidelobe Based on Nullspace

Optimal Synthesis of Array Focused Power Pattern With Arbitrary Polarization and Low Sidelobe Based on Nullspace