Photonic Spin Hall Effect Research Articles

Revisiting physical mechanism of longitudinal photonic spin splitting and Goos-Hänchen shift

The intrinsic connection between the transverse photonic spin Hall effect (PSHE) and the Imbert–Fedorov shift has been well characterized. However, physical insights into the longitudinal photonic spin splitting associated with the Goos-Hänchen (GH) shift remain elusive. This paper aims to expand the theory of the PSHE generation mechanism from the transverse to the longitudinal case by examining the reflection of each spin component from an arbitrarily linearly polarized incident Gaussian beam on the air-dielectric interface. Unlike the transverse case, both spin-maintained and spin-flipped modes exhibit non-zero longitudinal displacements, with the latter being affected by the second-order expansion term of the Fresnel reflection coefficient with respect to the in-plane wave-vector component. Meanwhile, the polarization angle plays a crucial role in determining the longitudinal PSHE since each reflected total spin component is a coherent superposition of these two corresponding modes. Remarkably, the imaginary part of the relative permittivity of the dielectric significantly affects the symmetry of the longitudinal PSHE. Furthermore, the GH shift results from a superposition of individual spin states’ longitudinal displacements, taking into account their energy weights. By incorporating the corresponding extrinsic orbital angular momentum, we explore the generation mechanism of the symmetric/asymmetric longitudinal PSHE. The unified physical framework elucidating the longitudinal photonic spin splitting and GH shift provides a comprehensive understanding of the fundamental origin of the PSHE and beam shifts, paving the way for potential applications in spin-controlled nanophotonics.

Enhanced photonic spin Hall effect and its sensing application via optical Tamm state based on nanocomposites

In this contribution, by combining the nanocomposite with distributed Bragg reflector, a simple multilayer structure to enhance the photonic spin Hall effect (PSHE) via optical Tamm state (OTS) for both horizontal (H) and vertical (V) polarized lights is presented. The structural parameters of nanocomposite layer (e.g., thickness and filling factor) have a significant influence on PSHE. The maximal spin shifts of 16.2 and 17.8 μm can be achieved for H and V polarized lights, respectively, which are attributed to strong excitation of OTS. Moreover, the spin shift is extremely sensitive to the refractive index changes of sensing medium, and a gas sensor with superior sensing performance is theoretically proposed for both H and V polarized beams. These findings provide an effective method to enhance the PSHE for both H and V polarized lights and therefore open an opportunity for developing PSHE refractive index sensors.

High-Performance Plasmonic Sensor for Detection of Cortisol Biomarker in Near Infrared With Photonic Spin Hall Effect

High-Performance Plasmonic Sensor for Detection of Cortisol Biomarker in Near Infrared With Photonic Spin Hall Effect

Short-Wave Infrared Janus Metastructure With Multitasking of Wide-Range Pressure Detection and High-Resolution Biosensing Based on Photonic Spin Hall Effect

Short-Wave Infrared Janus Metastructure With Multitasking of Wide-Range Pressure Detection and High-Resolution Biosensing Based on Photonic Spin Hall Effect

Photonic Spin Hall Effect based AQI sensor: Effect of concentration of PM2.5

Photonic Spin Hall Effect based AQI sensor: Effect of concentration of PM_2.5

Enhanced and tunable photonic spin Hall effect with optical Tamm states

The photonic spin Hall effect has attracted considerable attention for its potential applications in precision metrology and spin-based photonics. However, the spin-dependent transverse shift arising from this phenomenon is considerably weak and poses a challenge in terms of detection. Here, we present a novel technique to amplify the photonic spin Hall effect by exciting the optical Tamm states through an Au-distributed Bragg reflector. Our approach involves optimizing the thickness of the Au layer and the spacing layer, as well as adjusting the Fermi energy of graphene. The result is a remarkable transverse shift of up to 18 μm in the horizontal polarization state. Furthermore, we introduce graphene into the Au-distributed Bragg reflector to enable dynamic control of the photonic spin Hall effect by manipulating the Fermi energy of graphene. These findings represent an innovative platform for enhancing and actively controlling the photonic spin Hall effect with significant potential for spin-controlled optics.

Nonreciprocal Terahertz Beam Steering Manipulated by Magnetic Weyl Semimetal Metasurface Based on Universal Chirality‐ Wavevector‐ Magnetic Field Relation

AbstractMagnetic Weyl semimetal shows intriguing properties in both fundamental physics and potential applications. However, the complex relationship between nonreciprocal transmission and magnetic field manipulation in magnetic Weyl semimetal systems has not been generally clarified and fully utilized. Here, a universal Chirality–Wavevector–Magnetic field (C‐K‐B) relation is established in the magnetic Weyl semimetal system, which completely describes the spin topological band and its intrinsic polarization output in full space orientation under an arbitrary magnetic vector. This relation can provide complete guidance for the device design of nonreciprocal spin manipulation. Coupling this nonreciprocal mechanism with the photonic spin Hall effect of the geometric phased metasurface, a magnetic Weyl semimetal metasurface is constructed in the terahertz (THz) range, The experiments demonstrate the flexible THz beam steerings in a broad spatial dispersion range of ±25–±55° with four different working modes by only altering the biased magnetic vectors. Moreover, all these beam steering processes are accompanied by nonreciprocal isolating transmission with the isolation ratio reaching 27 dB. This C‐K‐B relation and active nonreciprocal beam steering devices are expected to prompt magneto‐optical devices and systems combined with echo isolation function in beam scanning, wavelength division multiplexing, and spin multiplexing.

Actively manipulating the temperature characteristics of photonic spin Hall effect in quasi-PT symmetric structure

The photonic spin Hall effect (PSHE) manifests itself as the spin-dependent transverse shift, and has many applications including precise metrology and optical sensing. However, some common ways to control PSHE have the limitation of less flexible and convenient manipulation. We report here an approach to actively manipulate the temperature characteristics of the PSHE in the quasi-PT symmetric structure by means of tunable graphene conductivity under optical pumping. The underlying mechanism is the flexible control of exceptional point by influencing graphene conductivity. We find that the PSHE shift is significantly enhanced near the exceptional point, and the enhanced PSHE shift can be manipulated by temperature. Moreover, the variation of temperature causes the inversion of the sign of the PSHE shift, and the temperature properties of the shift change as the optical pumping power varies. Based on the tunable PSHE shift, we design a temperature sensor with tunable sensitivity by combining weak measurement amplification techniques.

Hyperbolic shear polaritons and their potential applications

Hyperbolic shear polaritons recently emerge with widespread attention as a new form of polariton modes with broken symmetry due to shear lattices. Herein, the generation mechanism of hyperbolic shear polaritons is discussed in detail. The exotic anisotropic nanophotonic properties of hyperbolic shear polaritons as well as their potential applications (e.g., ultra-sensitive biomedical sensor, enhancing the near-field thermal radiation and the photonic spin Hall effect) are reviewed. Some existing issues and potential interesting directions for hyperbolic shear polaritons are outlined. This work could inspire more interest in anisotropic two-dimensional crystals and spur the quick generation of new photonic devices based on hyperbolic polaritons.

Photonic Spin Hall Effect as a Highly Sensitive Refractive Index Sensing Platform for Glucose

AbstractThis study presents an innovative refractive index (RI) sensor that measures glucose concentration by utilizing the photonic spin Hall effect (SHE) in a resonant optical tunneling effect (ROTE) structure. The ROTE structure consists of three InP layers with the high RI and two analyte layers (with a high‐low‐high‐low‐high RI distribution), in which glucose solution samples with the low RI are injected. By subjecting the InP layers to external bias‐assisted light, the photonic SHE can be flexibly manipulated, enabling the modulation of the sensing performance accordingly. It is found that the transverse shift of photonic SHE presents a large variation in response to the tiny change in glucose concentrations. By optimizing the parameters (i.e., intensity or wavelength) of bias light, the sensitivity of this sensor can reach as high as 735.7 µm RIU−1. Compared to traditional glucose sensors, this original work implements the novel photonic SHE with the superior sensing performance. Therefore, the proposed design shows promising potential for biomedical applications, such as medical diagnoses and drug discovery.

Broadband multifunctional metasurfaces enabling polarization multiplexed focused vortex array generation

Metasurfaces are ultrathin artificially engineered structures exquisitely designed to tailor the wavefront, polarization, and amplitude of incident light, offering a versatile platform for implementing compact and integrated photonics devices. Metasurface-based structured light generation has gained considerable attention in the scientific community for its various exotic applications, including optical communication, particle manipulation, and high-resolution lithography. State-of-the-art design techniques include polarization multiplexing, multiple vortices beam generation, and vortex arrays. However, there needs to be more techniques for generating polarization switchable vortex arrays, despite the apparent advantages in significant application fields, necessitating a simple design technique. Here, we present a straightforward design technique utilizing computer-generated holography (CGH) and photonic spin Hall effect (PHSE) to realize a metadevice platform capable of generating broadband multiple optical vortex arrays with switchable polarization output. Our approach involves designing phase masks for the vortex arrays using CGH, which are then encoded onto the metasurface. By leveraging PSHE, the designed metasurfaces produce the desired optical response depending on the input polarization state. Using the proposed design technique as proof of concept, different all-dielectric metasurfaces capable of generating optical vortex arrays of different dimensions are demonstrated. The results verify the effectiveness of the proposed methodology. The design has potential applications in data communications, storage, quantum computation, nanoscale physical manipulation, and microscopy.

Near-Field Observation of the Photonic Spin Hall Effect.

The photonic spin Hall effect, referring to the spatial separation of photons with opposite spins due to spin-orbit interactions, has enabled potential for various spin-sensitive applications and devices. Here, using scattering-type near-field scanning optical microscopy, we observe spin-orbit interactions introduced by a subwavelength semiring antenna integrated in a plasmonic circuit. Clear evidence of unidirectional excitation of surface plasmon polaritons is obtained by direct comparison of the amplitude- and phase-resolved near-field maps of the plasmonic nanocircuit under excitation with photons of opposite spin states coupled to a plasmonic nanoantenna. We present details of the antenna design and experimental methods to investigate the spatial variation of complex electromagnetic fields in a spin-sensitive plasmonic circuit. The reported findings offer valuable insights into the generation, characterization, and application of the photonic spin Hall effect in photonic integrated circuits for future and emerging spin-selective nanophotonic systems.

Photonic spin Hall effect in uniaxially strained graphene

Graphene is one of the thinnest conductive materials which possesses unique mechanical, electronic, optical, and magnetic properties. Owing to its inherent unique mechanical flexibility and strength, it has potential applications in various flexible nanophotonic devices. In this paper, we present theoretical investigations of the spin Hall effect of a light beam reflected from the surface of the strained graphene substrate system subjected to uniaxial strain. Using appropriate boundary conditions for the incident and reflected beams based on the angular spectrum analysis, we derive mathematical expressions for the transverse photonic spin Hall effect (PSHE) for the strained graphene. By tuning the applied strain along zigzag and armchair orientations, we explore the giant PSHE in the graphene substrate system. We show the impact of chemical potential, incident photon energy, and applied strain on the photonic spin Hall shifts. We believe that the PSHE may thus serve as a versatile tool to probe the applied strain in novel 2D materials.

Optimal weak measurement scheme for chiral molecular detection based on photonic spin Hall effect.

In this paper, we propose a precision method to measure the chiroptical signal of Artemisinin solutions using the photonic spin Hall effect (PSHE) on the Ce:YIG-YIG-SiO2 structure as a probe. The effects of transmission distance, incident angles, applied magnetic fields of different directions, and beam waist of light on the weak measurement system are analytically investigated through simulations. It is found that decreasing the beam waist of the incident spot, increasing the incident angle, increasing the transmission distance, and adding a longitudinal magnetic field is conducive to enhancing the amplification transverse shift of PSHE, thus the measurement sensitivity is greatly improved. Based on the optimal weak measurement scheme, the detection limit for concentration measurement of artemisinin based on optical rotatory (OR) was reduced to 0.05 mg/ml. The measurement precision of the OR angle has been improved to 10-7rad.

Plexcitonic system for high photonic spin Hall effect

The photonic spin Hall effect (PSHE) has been intensively studied and widely applied, especially in spin photonics. In this paper, we present the analysis of PSHE in the Plexcitonic system. The signature of the Plexciton is studied by implanting an organic semiconductor layer over the plasmon active metal. We report a high spin-dependent transverse shift of ∼ 60 μm, which is ∼200-fold larger than that of the pure Plasmonic counterpart. The underlying mechanism of PSHE is explained in the circular-polarization basis using the concept of superposition of abnormal and normal modes. It is observed that the transverse shift is highly sensitive to the alterations in the environmental refractive indices leading to its application as a highly sensitive PSHE-based refractometer, with a high sensitivity of 81°/RIU. We believe these results may open pathways for modulating the PSHE and developing nanophotonic applications such as advanced sensors and next-generation optical devices.

Rotational photonic spin Hall effect

Abstract Multidimensional manipulation of photonic spin Hall effect (PSHE) has attracted considerable interest due to its potential in a wide variety of spin-based applications. Plenty of research efforts have been devoted to transverse or longitudinal spin-dependent splitting; however, the splitting pattern that can self-rotate in a three-dimensional (3-D) space appears to be missing in literature. In this paper, we introduce a novel 3-D rotational PSHE, which can be realized and tuned using well-designed Pancharatnam–Berry phase metasurfaces. To demonstrate this phenomenon, we first show that when a single dielectric metasurface is used, the lobe-structured spin-splitting patterns on the transverse planes rotate and evolve along the propagation path. Then, we present that under two cascaded metasurfaces, the rotation angle of the splitting patterns are tunable by adjusting the relative rotation angle between the two metasurfaces. Finally, we manifest that the lobe number of the two spin-dependent splitting patterns can be independently controlled once we introduce a dynamic phase, which produces an asymmetrical rotational PSHE. The demonstrated phenomena can be used to achieve active manipulation of spin photons in multiple dimensions, and the developed device might find potential applications in various areas, e.g., optical microscopy.

Ultrawide and unidirectional enhancements of a photonic spin Hall effect in a tilted uniaxial crystal.

Since the enhancement of the photonic spin Hall effect (PSHE) is limited around the Brewster's angle, the scientific problem of how to extend the range of incident angles and to keep them unidirectional for the enhanced PSHE remains open. Here, we propose an effective method to achieve the ultrawide angle and unidirectional enhancement of PSHE via the omnidirectional Brewster's effect in a tilted uniaxial crystal. By properly setting the permittivity and the optical axial angle of the uniaxial crystal, the omnidirectional Brewster's effect can be obtained to realize an ultrawide angle enhancement of the PSHE. Then, by appropriately deviating the optical axial angle, the ultrawide enhancement of the PSHE can be achieved within the maximum incident angle range of 60° with unchanged direction. These findings inspire an unprecedented route to facilitate the applications in precision measurement and spin-dependent devices.

Photonic spin Hall effect in twisted bilayer phosphorene

We investigate the photonic spin Hall effect of a linearly polarized Gaussian beam reflected on the surface of twisted bilayer phosphorene. The photonic spin shift depends strongly on optical resonance behavior, which is determined by the twist angle. The magnified spin shift near the Brewster angle is sensitive to the twist angle and can be fitted by numerical models. In particular, the spin shifts in the terahertz region of frequency are well within the current experimental detection precision. Our findings suggest that the photonic spin Hall effect is promising for precise characterization of the optical property and the structure of twisted bilayer phosphorene.

Photonic spin Hall effect in a graphene-incorporated quasi-PT symmetric system and the miniaturization of nanophotonic devices.

By inserting the monolayer graphene between the balanced gain and loss layers, the graphene-incorporated quasi-parity-time (PT) symmetric structure is established. In this contribution, the introduction of graphene provides a new degree of freedom to manipulate the optical performance as well as the photonic spin Hall effect (SHE). The coherent perfect absorption (CPA)-laser mode still remains in the graphene-incorporated quasi-PT symmetric system, and the spin shift of transmitted light can be significantly enhanced (i.e.,up to its upper limitation) in the vicinity of CPA-laser mode, which is 18 times larger than the value of a simple PT symmetric structure. In addition, the excitation of the CPA-laser mode and the huge spin shift of transmitted light can be achieved with the thin gain/loss layers, which will be conducive to the miniaturization of nanophotonic devices based on the photonic SHE in the future.

Photonic spin Hall effect driven broadband multi-focus dielectric metalens.

The multi-focus metalens can couple the light into multiple channels in optical interconnections, which is beneficial to the development of planar, miniaturized, and integrated components. We propose broadband photonic spin Hall effect (PSHE) driven multi-focus metalenses, in which each nanobrick plays a positive role for all focal points. Three PSHE driven metalenses with four, six, and eight focal points have been designed and investigated, respectively. Under the incidences of left-/right-handed circularly polarized (LCP/RCP) light, these metalenses can generate regularly distributed two, three, and four RCP/LCP focal points, respectively. The uniformity of the focusing intensity has been investigated in detail by designing an additional four six-focus metalenses with different focus distributions. The uniqueness of these metalenses makes this design philosophy very attractive for applications in spin photonics, compact polarization detection, multi-imaging systems, and information processing systems.