Spin Hall Effect Of Light Research Articles

Research on the performance of the spin Hall effect of light based on a magnetized plasma layered structure

In this paper, a new, to the best of our knowledge, engineering structure is proposed to explore the sensitivity of the performance of the spin Hall effect of light (SHEL) to external parameters. The structure is composed of a glass layer, air layer, and middle layer, which is made up of a magnetized plasma layered structure. The simulation results show that all of the plasma frequencies, the frequency of incident light, the number of magnetized plasma layers, and the magnetic field distribution do make a difference to the performance of the SHEL. In the calculation process, the transfer matrix method is used to obtain reflection coefficients and then obtains the lateral displacement. The computed results demonstrate that the horizontal displacement of SHEL gets to the largest value when the plasma frequency is quadruple ω p 0 , and the horizontal displacement trails off while the turning point veers to the right with the augmentation of the frequency of incident light. Furthermore, the horizontal displacement of SHEL will suffer from an increasing number of magnetized plasma layers. It is also confirmed that the magnetic field distribution has some effects on the behavior of SHEL. Through these findings, certain parameters can be measured by measuring the angle of shift and the size of the horizontal displacements, such as the refractive index. Thus, our research is of great help to some applications, such as sensors.

Focused linearly-polarized-light scattering from a silver nanowire: Experimental characterization of the optical spin-Hall effect

Spin-orbit interactions (SOI) are a set of sub-wavelength optical phenomenon in which spin and spatial degrees of freedom of light are intrinsically coupled. One of the unique example of SOI, spin-Hall effect of light (SHEL) has been an area of extensive research with potential applications in spin controlled photonic devices as well as emerging fields of spinoptics and spintronics. Here, we report our experimental study on SHEL due to forward scattering of focused linearly polarized Gaussian and Hermite-Gaussian ($\textrm{HG}_{10}$) beams from a silver nanowire (AgNW). Spin dependent anti-symmetric intensity patterns are obtained when the polarization of the scattered light is analysed. The corresponding spin-Hall signal is obtained by computing the far-field longitudinal spin density ($s_3$). Furthermore, by comparing the $s_3$ distributions, significant enhancement of the spin-Hall signal is found for $\textrm{HG}_{10}$ beam compared to Gaussian beam. The investigation of the optical fields at the focal plane of the objective lens reveals the generation of longitudinally spinning fields as the primary reason for the effects. The experimental results are corroborated by 3-dimensional numerical simulations. The results lead to better understanding of SOI and can have direct implications on chip-scale spin assisted photonic devices.

Magneto-optical spin Hall effect of light controlled by thermo-optical effect

In this paper, an experimental method of magneto-optical spin Hall effect of light (MOSHEL) based on thermo-optical control is designed. First, we design and implement a pilot experiment—the SHEL experiment controlled by thermo-optical. According to the experiment, it is concluded that the increase of the temperature of the thermo-optical medium will have an important influence on the corresponding thermo-optical spin Hall effect of light (TOSHEL). Accordingly, we designed a device that controls the SHEL in magneto-optical-thermo-optical (MO-TO) two-dimension that uses the thermo-optical effect to simultaneously control the intrinsic TOSHEL and MOSHEL.

Spin Hall Effect of Light on the Surface of Functional Photonic Crystal

Spin Hall Effect of Light on the Surface of Functional Photonic Crystal

Enhanced spin Hall effect of light scattering on a meta-atom with bianisotropy

We reveal an interesting phenomenon of enhanced polarization-dependent transverse deflection of scattered light on a meta-atom with bianisotropy. The relationship between the spin-dependent shift and the bianisotropy is demonstrated. Unlike the usual particle, the obvious transverse scattering can be obtained by the bianisotropy. Furthermore, the lateral optical force exerted on the bianisotropic meta-atom is inevitable due to the spin Hall effect of light. This work provides a way to achieve an enhanced spin Hall effect of light and offers a platform to study the interaction between light and meta-atom with bianisotropy.

Spin Hall Effect of Light with Near‐Unity Efficiency in the Microwave

AbstractThe spin Hall effect of light (SHEL) refers to a transverse and spin‐dependent shift of light in real space at an optical interface. Previous studies of enhancing the SHEL have involved extremely low efficiency, and achieving a large SHEL and high efficiency simultaneously has never been reported. Here, an approach using anisotropic impedance mismatching to attain a large SHEL with near‐unity efficiency in the microwave spectrum is proposed. A wire medium that has a near‐unity transmission for one polarization and low transmission for the other is used to achieve high efficiency. The spin‐dependent splitting is experimentally confirmed by measuring transmission coefficients and the spatial profile of Stokes parameters. The large SHEL with near‐unity efficiency will enable highly efficient devices with spin‐selective functionalities.

Spin Hall effect of light in inhomogeneous axion field

We study the spin transport of light in weakly inhomogeneous axion field in a flat Robertson-Walker universe and derive the spin Hall effect for circularly polarized rays. Regarding primordial quantum fluctuations of the axion field in the de Sitter phase as the origin of the inhomogeneity, we show that the conformal invariance of the correlator determines the root-mean-square (r.m.s) fluctuation of the path of circularly polarized cosmic rays. We explain how the r.m.s fluctuation can be experimentally determined.

Measurement of the magnetic properties of thin films based on the spin Hall effect of light.

Using the spin Hall effect of light, this work proposes a measurement technique of the magnetic properties of thin films. The beam shift of the spin Hall effect of light is used to replace the magneto-optical Kerr rotation angle as a parameter to characterize the magnetism of thin films. The technique can easily achieve an accuracy of 10-6 rad of the magneto-optical Kerr rotation angle which can, in theory, be further improved to 10-8 rad. We also proposed two methods to solve the problem of the exceeding linear response region of the measurement under high magnetic field intensity, making it more conducive to practical application. This technique has great potential for application in the magnetic measurement of ultra-thin films with particular emphasis on thicknesses within several atomic layers.

Back Cover: Probing Proximity‐Tailored High Spin–Orbit Coupling in 2D Materials (Adv. Quantum Technol. 9/2020)

Simultaneous extraction of the magnetic and spin-orbit coupling (SOC) information of an interface using the weak measurement assisted spin-Hall effect of light (SHEL) is demonstrated as a novel probe to characterize materials' magnetic properties, see article number 2000042 by Karthik V. Raman, Tharangattu N. Narayanan, Nirmal K. Viswanathan, and co-workers. A heterostructure of Fe and MoS2 monolayers is shown for enhanced SOC due to the proximity effect, which is proven via SHEL method and then confirmed using magneto-optic Kerr effect (MOKE) studies.

Gravitational spin Hall effect of light

The propagation of electromagnetic waves in vacuum is often described within the geometrical optics approximation, which predicts that wave rays follow null geodesics. However, this model is valid only in the limit of infinitely high frequencies. At large but finite frequencies, diffraction can still be negligible, but the ray dynamics becomes affected by the evolution of the wave polarization. Hence, rays can deviate from null geodesics, which is known as the gravitational spin Hall effect of light. In the literature, this effect has been calculated ad hoc for a number of special cases, but no general description has been proposed. Here, we present a covariant Wentzel-Kramers-Brillouin analysis from first principles for the propagation of light in arbitrary curved spacetimes. We obtain polarization-dependent ray equations describing the gravitational spin Hall effect of light. We also present numerical examples of polarization-dependent ray dynamics in the Schwarzschild spacetime, and the magnitude of the effect is briefly discussed. The analysis reported here is analogous to that of the spin Hall effect of light in inhomogeneous media, which has been experimentally verified.

Probing Proximity‐Tailored High Spin–Orbit Coupling in 2D Materials

AbstractProximity‐induced tuning of spin–orbit coupling (SOC) is of paramount importance in emerging magnetic materials and in spintronics. Probing the above SOC via light–matter interaction assisted methods provides a novel route to investigate interesting material phenomena. Here, the proximity studies in a heterostructure of monolayer molybdenum disulfide (MS) and iron (Fe) to enhance and tune the interfacial SOC are reported. The augmented SOC of the MSFe heterostructure arises due to interfacial charge transfer, and is probed using magneto‐optic Kerr effect and a novel optical technique utilizing the spin Hall effect of light. Measuring the changes in the state of polarization of light reflected from the sample via weak measurement provides direct access to the real and imaginary parts of the complex weak value and, hence, the underlying SOC and induced magnetic effects from a single experiment. The results obtained are confirmed using other experimental and simulation tools.

Magneto-optical spin Hall effect of light and its application in refractive index detection

The spin Hall effect of light (SHEL) is a photonic version of the spin Hall effect in electronic systems, and it has been a focused research area in the recent ten years. However, due to the lack of effective methods dynamic modulation of spin-dependent splitting, the practical application of SHEL has remained a challenge, still urgently waiting to be resolved. In recent years, SHEL has been applied to the precise measurement and sensing of various physical quantities. Now, how to make SHEL measurement flexible is the research direction of researchers The magneto-optical spin Hall effect of light (MOSHEL) is a useful attempt to implement a dynamic transformation of SHEL. The spin–orbit coupling or non-reciprocal phase shift caused by magnetic fields in different directions applied to magneto-optical materials can be flexibly and timely controlled. This paper reports our studies on the magneto-optical effect in multilayer structure. For the first time, the refractive index of very low concentration sample solution is sensed through the method of weak measurement under the condition of transverse magneto-optical Kerr effect. The ultra-high sensitivity of 2.9×104μm/RIU was measured under the optimum parameters. This is of great significance in advancing the practical application of MOSHEL.

Geometric phase for multidimensional manipulation of photonics spin Hall effect and helicity-dependent imaging

Abstract The spin Hall effect of light, associated with spin-orbit interactions, describes a transport phenomenon with optical spin-dependent splitting, leading to a plethora of applications such as sensing, imaging, and spin-controlled nanophotonics. Although geometric meatsurfaces can mimic photonic spin Hall effect by spatially splitting left-hand circularly polarized and right-hand circularly polarized states of electromagnetic waves with anomalous refraction or reflection angles, the geometric phase generated by metasurfaces hinders metalenses to realize simultaneous focusing of different spin states, limiting further applications. Here, we propose and experimentally demonstrate an approach to realizing a spin Hall metalens that can focus terahertz waves with different spin states and flexibly manipulate spin-dependent focal points in multiple spatial dimensions based on a pure geometric phase. A dielectric metasurface consisting of micropillars with identical shape and different in-plane orientations is designed to realize the multidimensional manipulation of photonics spin Hall effect in terahertz region. Furthermore, helicity-dependent imaging is demonstrated by the terahertz spin Hall metalens. The uniqueness and robust approach for manipulating spin photons may have a significant impact on designing ultra-compact and multifunctional devices and spin photonics devices.

Impact of the pitch angle on the spin Hall effect of light weak measurement.

The spin Hall effect of light (SHEL), as a photonic analogue of the spin Hall effect, has been widely studied for manipulating spin-polarized photons and precision metrology. In this work, a physical model is established to reveal the impact of the interface pitch angle on the SHEL accompanied by the Imbert-Fedorov angular shift simultaneously. Then, a modified weak measurement technique is proposed in this case to amplify the spin shift experimentally, and the results agree well with the theoretical prediction. Interestingly, the amplified transverse shift is quite sensitive to the variation of the interface pitch angle, and the performance provides a simple and effective method for precise pitch angle sensing with a minimum observable angle of 6.6 × 10-5°.

Spin Hall effect of tunneling mode in one-dimensional photonic crystal based on frustrated total internal reflection

The spin Hall effect of light (SHEL) upon reflection and refraction of p and s waves in one-dimensional photonic crystal (1DPC) tunneling mode based on frustrated total internal reflection (FTIR) is investigated in this paper. We discuss the SHEL in three different cases based on both theoretical derivation and simulation. These results have demonstrated that the SHEL in 1DPC can be enhanced significantly when the designed 1DPC structure simultaneously satisfies both high reflection coefficient of p-wave and high transmission rate of s-wave. A transverse shift of 28.47 μm (equivalent to 45λin length) can be achieved in the structure without any amplification method, which is much larger than those previously reported in literature.

Lattice-dependent spin Hall effect of light in a Weyl semimetal.

We systematically study the lattice-dependent spin Hall effect of light (SHEL) in a Weyl semimetal (WSM) by considering left-handed polarization of the incident beam, and propose a new simple method to sense the lattice spacing precisely. It is revealed that the lattice spacing plays as essential a role as the Weyl points separation in the influences on the SHEL, and the variations of SHEL shifts are closely related to the real part of Hall conductivity. Specifically, the SHEL shifts increase to the peak values first and then decrease gradually with the increase of lattice spacing, and a quantitative relationship between the SHEL and the lattice spacing is established. By simulating weak measurement experiments, the lattice-dependent SHEL shifts are amplified and measured in desirable accuracies. Subsequently, we propose a method of precisely sensing the lattice spacing based on the amplified SHEL shifts. These researches provide theoretical basis for manipulating the SHEL in WSMs, and may open the possibility of fabricating the WSM parameter sensors.

Controlling photonic spin Hall effect based on tunable surface plasmon resonance with an N−type coherent medium

We propose a scheme to control the spin Hall effect (SHE) of light reflected from a Kretschmann configuration containing an N-type coherent atomic medium. Owing to the excitation of surface plasmon resonance (SPR), enhanced spin splitting occurs in the reflection dip for TM-polarized incident light. The magnitude and sign of the transverse shifts of spin components depend on the system internal damping which is closely related to the absorption coefficient of atoms. There is an optimal absorption around which the spin components undergo large transverse displacements. We also show that the direction of the photonic spin accumulations can be switched between positive and negative values by adjusting the system parameters. In addition, the resonance angle of SPR varies linearly with the refractivity of the medium. We can therefore coherently control the peak position of the transverse shift. Compared to the conventional SPR-based systems, the proposed scheme provides a more flexible pathway for manipulating and enhancing the SHE of light without changing the structure. This tunable SHE may find applications in spin photonic devices.

Anomalous amplification in almost-balanced weak measurement for measuring spin Hall effect of light.

In this paper, a method to measure the tiny spin splitting of the spin Hall effect of light (SHEL) using the almost-balanced weak measurement (ABWM) is presented. The ABWM technique uses two orthogonal post-selected states to record all of the information, which is a precise measurement method being different from the standard weak measurement (SWM). The theory model to describe the SHEL measurement based on ABWM is established. As results, the ABWM scheme has a larger amplification factor, reaching ∼105, which is nearly one order of magnitude higher than that of the SWM. When the post-selected angle is less than a certain value, the sensitivity and amplification factor of the ABWM scheme are higher than those of the SWM scheme, while the measurement precision and SNR of the ABWM technique are comparable to those of the SWM scheme. This research may have great potential for the precision metrology or sensing field based on the SHEL measurement.

Three-dimensional spin Hall effect of light in tight focusing

We theoretically propose the realization of a three-dimensional (3D) spin Hall effect (SHE) of light by tightly focusing a linearly polarized light. Owing to the spin-orbital interaction in focusing, the left and right circularly polarized components of light are partly converted into each other, acquiring opposite vortex phases. As the superposition of the vortex and the initial vortex-free light, the two polarized components exhibit spiral intensity patterns which rotate oppositely around the propagation axis. Consequently, the two spin components are distributed alternatively in both the azimuthal and the longitudinal directions, leading to a 3D array of split spin components, and the transverse intensity is also spit asynchronously. Moreover, that array is rotatable by the incident polarization, and the longitudinal spacing in the array can be controlled by the numerical aperture of the lens. The 3D SHE of light finds an additional degree of freedom available to control the spin state of the photon, which may be valuable in optical manipulation and quantum information.

Spatial differential operation and edge detection based on the geometric spin Hall effect of light.

Unlike the conventional spin Hall effect of light (SHEL) originating from the light-matter interaction, the spin-dependent splitting in the geometric SHEL is purely a geometric effect and independent from the properties of matter. Here it is shown that the geometric SHEL is not only of fundamental theoretical interest in understanding the spin-orbit interaction of light, but also sheds light on important technological applications. This Letter describes the theoretical foundation and experimental realization of optical differential operation and one-dimensional edge detection based on the geometric SHEL.