Photonic Hall Effect Research Articles

Photonic Hall Effect via Optically-Induced Near-Field Asymmetry in Arrays of Au Cross-Shaped Nanoantennas

Photonic Hall Effect via Optically-Induced Near-Field Asymmetry in Arrays of Au Cross-Shaped Nanoantennas

Observation of the photonic Hall effect and photonic magnetoresistance in random lasers

Modulation of scattering in random lasers (RLs) by magnetic fields has attracted much attention due to its rich physical insights. We fabricate magnetic gain polymer optical fiber to generate RLs. From macroscopic experimental phenomena, with the increase of the magnetic field strength, the magnetic transverse photocurrent exists in disordered multiple scattering of RLs and the emission intensity of RLs decreases, which is the experimental observation of photonic Hall effect (PHE) and photonic magnetoresistance (PMR) in RLs. At the microscopic level, based on the field dependence theory of magnetic disorder in scattered nanoparticles and the replica symmetry breaking theory, the magnetic-induced transverse diffusion of photons reduces the scattering disorder, and then decreases the intensity fluctuation disorder of RLs. Our work establishes a connection between the above two effects and RLs, visualizes the influence of magnetic field on RL scattering at the microscopic level, which is crucial for the design of RLs.

Observation of Unidirectional Bulk Modes and Robust Edge Modes in Triangular Photonic Crystals

AbstractThe valley contrasting physics in photonic systems gives rise to many interesting phenomena such as photonic valley Hall effect and robust valley transport. However, most reported valley photonic crystals are demonstrated in the honeycomb lattice. Here, unidirectional bulk modes and robust edge modes are numerically and experimentally shown in triangular photonic crystals. By switching the phase vortex of an input chiral source, dynamic unidirectional propagation of bulk modes at different valleys is observed. Unidirectional edge modes are also demonstrated on the domain wall between two distinct triangular photonic crystals. In addition, robust edge modes around sharp corners are experimentally confirmed. This work paves the way for the realization of dynamic unidirectional photonic transport and robust valley transport in photonic crystals.

Asymmetry spin-polarization Fermi arc and topological chiral beam splitter with the triply degenerate point in metamaterial.

Dirac points (DPs) and Weyl points (WPs) have received much attention in photonic crystals (PhCs) and three-dimensional (3D) metamaterials research due to the robust surface states and Fermi arcs. In this work, two pairs of triply degenerate points (TDPs) have been proposed in a 3D metamaterial by breaking the time reversal symmetry (T) with an external magnetic field. Based on these TDPs, two pairs of asymmetric surface states with spin-polarization are revealed, and a topological chiral beam splitter is demonstrated showing the different propagating directions of the right-handed polarization (RCP) and left-handed polarization (LCP) lights. Remarkably, we can achieve unidirectional propagation with RCP or LCP even excited by a linear source owing to the asymmetry surface state. Our work provides a new, to the best of our knowledge, platform to study spin-polarization surface states and the enhanced spin photonic Hall effect in the metamaterials.

Revisiting the photonic orbital Hall effect with the vortex mode decomposition

The photonic orbital Hall effect (POHE) refers to the vortex-dependent beam shifts, which is generally believed to result from the conversion of intrinsic orbital angular momentum (IOAM) to extrinsic orbital angular momentum (EOAM). However, the physical mechanism of the POHE, such as how the IOAM is converted to the EOAM, remains further elucidation. In this paper, we re-examine the POHE of a vortex beam with additional IOAM illuminating at an optically thin slab by means of vortex mode decomposition. By considering the competition and coupling between the radial and azimuthal vortex harmonics of the abnormal mode in the transmitted beam, it is found that the underlying mechanism of the POHE is in fact a spin-to-orbital angular momentum (OAM) conversion process. And the IOAM carried by the incident beam is directly superimposed on the OAM obtained during the conversion. Our findings not only offer an alternative perspective for understanding the POHE, but also exhibit application potential in orbit–orbit and spin–orbit optical components.

Eigenmode analysis of dynamical many-body near-field radiative heat transfer mediated by an external magnetic field

• Eigenmode analysis is applied to the dynamical many-body near-field radiative heat transfer under an external magnetic field. • We identify near-field and far-field thermalization modes and the roles of magneto-resistance effect and directional heat flow. • The near-field mode can be largely slowed down by the magnetic field and is highly tunable via variation of the direction of the magnetic field. • The far-field mode is greatly enhanced by the magnetic field due to extra contribution of circular resonances. • The far-field mode is independent on the particle-particle near-field interaction, the spatial arrangement of the cluster and the direction of the magnetic field. In this work, we apply eigenmode analysis to the dynamical many-body radiative heat transfer (RHT) of an ensemble of magneto-optical (MO) nanoparticles under an external magnetic field. With the eigenmode analysis, we identify near-field and far-field modes of thermalization, each mode can dominate the dynamical many-body RHT depending on the temperature distribution of the nanostructures. The near-field thermalization modes, dominated by near-field RHT, tend to distribute the thermal energy uniformly through the ensemble at small time scales. The eigenmode analysis shows that the thermal magneto-resistance effect can slow down the near-field mode by an order of magnitude, which is highly sensitive to the direction of the magnetic field. The far-field mode is activated upon reaching uniform temperature distribution and occurs at much larger time scales, in which the nanoparticles thermalize with the background via far-field RHT, independent of the near-field interaction, the spatial arrangement of the ensemble and the direction of the magnetic field. The far-field mode, in contrast, can be greatly accelerated by the magnetic field due to the extra contribution of circular resonances. The eigenmode analysis also identifies circular thermalization modes in certain configurations, indicating the emergence of persistent directional heat flow and the thermal photonic Hall effect. Aided with eigenmode analysis, our work gives deep physical insights into the thermalization process of MO many-body nanostructures, revealing the important role of the magnetic field in the temporal and spatial control of many-body near-field RHT.

Photonic spin Hall effect from quantum kinetic theory in curved spacetime

Based on quantum field theory, we formulate the Wigner function and quantum kinetic theory for polarized photons in curved spacetimes which admit a covariantly constant timelike vector. From this framework, the photonic chiral/zilch vortical effects are reproduced in a rigidly rotating coordinate. In a spatially inhomogeneous coordinate, we derive the spin Hall effect for the photon helicity current and energy current in equilibrium. Our derivation reveals that such photonic Hall effect are related to the photonic vortical effect via the Lorentz invariance and their transport coefficients match each other.

Tunable propagation of waveguide modes in multichannel two-dimensional photonic crystal waveguide

Photonic Hall effect (PHE) can be realized in the multiple-channel photonic crystal waveguide. By modulating the polarization state of the incident light, the light can propagate in any one or more of the four channels of the waveguide, while the light energy in the other channels is very weak. Its fascinating behavior can be explained by the theory of interference of the two component waves. We believe that our results will have important applications in photonic integrated circuits.

Photonic Hall effect for a 1D-dimensional graphene-based photonic crystal with two defects

The presence of two defect layers in a one-dimensional photonic crystal which could be described numerically by the transfer matrix model becomes important when two defects modes might be controlled by the number of the middle layers. In this work, we compute the transmission spectra of a 1D photonic crystal with two graphene-based defect layers in the presence of an applied constant magnetic field. It is observed that an additional defect mode shows up at the lower edge of the photonic bandgap of the optical structure which could to be tuned by the Fermi energy, the intensity of the magnetic field and also the number of the layers between the defects. In addition, we investigated the effect of decreasing the number of middle layers on the transmission spectra of the photonic device.

Photonic quantum Hall effect and multiplexed light sources of large orbital angular momenta

The quantum Hall effect involves electrons confined to a two-dimensional plane subject to a perpendicular magnetic field, but it also has a photonic analogue1–6. Using heterostructures based on structured semiconductors on a magnetic substrate, we introduce compact and integrated coherent light sources of large orbital angular momenta7 based on the photonic quantum Hall effect1–6. The photonic quantum Hall effect enables the direct and integrated generation of coherent orbital angular momenta beams of large quantum numbers from light travelling in leaky circular orbits at the interface between two topologically dissimilar photonic structures. Our work gives direct access to the infinite number of orbital angular momenta basis elements and will thus enable multiplexed quantum light sources for communication and imaging applications. A topological photonic crystal design directly generates light that carries orbital angular momentum with high quantum numbers. The beam contains several different states at the same time, promising integrated and multiplexed light sources.

Manipulating the photonic Hall effect with hybrid Mie-exciton resonances

We examine the far-field optical response, under-plane wave excitation in the presence of a static magnetic field, of core-shell nanoparticles involving a gyroelectric component, either as the inner or the outer layer, through analytic calculations based on appropriately extended Mie theory. We focus on absorption and scattering of light by bismuth-substituted yttrium iron garnet (Bi:YIG) nanospheres and nanoshells, combined with excitonic materials such as organic-molecule aggregates or two-dimensional transition-metal dichalcogenides, and discuss the hybrid character of the modes emerging from the coupling of the two constituents. We observe the excitation of strong magneto-optic phenomena and explore, in particular, the response and tunability of a magneto-transverse light current, indicative of the photonic Hall effect. We show how interaction between the Bi:YIG and excitonic layers leads to a pair of narrow bands of highly directional scattering, emerging from the aforementioned hybridization, which can be tuned at will by adjusting the geometrical or optical parameters of the system. Our theoretical study introduces optically anisotropic media as promising templates for strong coupling in nanophotonics, offering a means to combine tunable magnetic and optical properties, with potential implications both in the design of all-dielectric photonic devices but also in novel clinical applications.

Topological Insulator Laser Using Valley-Hall Photonic Crystals

Topological photonics has recently been proved a robust framework for manipulating light. Active topological photonic systems, in particular, enable richer fundamental physics by employing nonlinear light-matter interactions, thereby opening a new landscape for applications such as topological lasing. Here we report an all-dielectric topological insulator laser scheme based on semiconductor cavities formed by topologically distinct Kagome photonic crystals. The proposed planar semiconductor Kagome lattice allows broadband edge states below the light line due to photonic valley hall effect in telecommunication region, which provides a new route to retrieve nontrivial photonic topology and to develop integrated topological systems for robust light generation and transport.

Efficient Optical Angular Momentum Manipulation for Compact Multiplexing and Demultiplexing Using a Dielectric Metasurface

AbstractAngular momentum (AM), one of the most basic physical properties of light, has attracted great interest of the scientific community due to its significant values in high‐capacity optical communication. To realize AM multiplexing and demultiplexing, the methods based on metallic metasurface are proposed, which suffers from huge Ohmic losses. Besides, additional coupling elements are necessary for coupling the output light into single‐mode waveguides. Here, an efficient and focused AM multiplexing and demultiplexing system based on dielectric metasurfaces are proposed and investigated. Employing the off‐axis technique and spin photonic Hall effect, the orbital angular momentum (OAM) and spin angular momentum (SAM) multiplexing/demultiplexing can be achieved. A 10‐channel AM multiplexing/demultiplexing system based on the proposed method is demonstrated. The demultiplexing efficiencies for all AM stats are above 8% and the maximum crosstalk among all AM states is −12.8 dB, which exhibits an excellent performance of the proposed metasurface for the AM demultiplexing. Furthermore, the output light is focused at the focal plane, which can be directly coupled into the single‐mode waveguides and improve the compactness of the system. The proposed method provides an effective way for AM multiplexing and demultiplexing, which possess a crucial potential for high‐capacity optical communication applications.

Tunable Electromagnetic Flow Control in Valley Photonic Crystal Waveguides

The exploration of binary valley degree of freedom in topological photonic systems has inspired many intriguing optical phenomena such as photonic Hall effect, robust delay lines, and perfect out-coupling refraction. In this work, we experimentally demonstrate the tunability of light flow in a valley photonic crystal waveguide. By continuously controlling the phase difference of microwave monopolar antenna array, the flow of light can split into different directions according to the charily of phase vortex, and the splitting ratio varies smoothly from 0.9 to 0.1. Topological valley transport of edge states is also observed at photonic domain wall. Tunable edge state dispersion, i.e., from gapless valley dependent modes to gapped flat bands, is found at the photonic boundary between a valley photonic crystal waveguide and a perfect electric conductor, leading to the tunable frequency bandwidth of high transmission. Our work paves a way to the controllability and dynamic modulations of light flow in topological photonic systems.

The Influence of Incident Power on the Magnetic Fluid Sensor Sensitivity Based on Optical Transmission Properties

Sensitivity is a critical characteristic of sensors, and increasing the sensitivity of the sensor is valuable for measurement study. Incident power has an important influence on the sensitivity of magnetic fluid sensors based on optical transmission properties. Variation in the magnetic field sensitivity at different incident powers was investigated by the measurement of transmitted power through the magnetic fluid sensors. As the magnetic field strength increases, the sensitivity variation of the magnetic fluid film sensor can be divided into four stages: first decreasing sharply, secondly increasing, then decreasing gradually, and finally tending toward a small stable value. The magnitudes of the change in the sensor sensitivity are influenced by the incident power, because the structural pattern of the nano-magnetic particles in the magnetic fluid sensor changes, the Soret effect and the Photonic Hall effect co-define the sensing system. In the weak magnetic field range, when a higher sensitivity is required, it is appropriate to select a larger incident power; however, in a large magnetic field range, when a higher sensitivity is required, a small incident power should be selected. Therefore, the magnetic fluid film sensor exhibits different sensitivity characteristics if different incident power values are chosen. The appropriate incident power can be selected according to the range of the magnetic field to be measured to improve the sensitivity in the magnetic field measurement study.

Photonic Hall effect

In this work, we report on the emergence of a photonic Hall effect (PHE) system within a narrow filtered background of a one-dimensional defective optical dielectric structure with graphene under the influence of a constant magnetic field regime. It is observed that at low temperature and relatively strong applied magnetic fields, electromagnetic defective transmission spectra corresponding to the two decoupled right- and left-handed polarized modes possess a step-like transmission feature which is referred to as “quantum Hall defect modes” (QHD modes or QHDs) in this paper. Tunable growing transitional transmission steps for QHDs with increasing magnetic field intensity were shown to be possible. Observation of sensitive magneto-transmission oscillations to the thermal excitations in the last plateaus slowly ascending toward unity is another special feature noted in this work. The results of this study, which is carried out based on rapid standard calculations for the transfer matrix approach is supplied with commercial simulations marking the first PHE system, promise an proper candidate for new photonic applications, especially new tunable magneto-based lenses and photonic magneto-thermal sensors.

Valley-controlled propagation of pseudospin states in bulk metacrystal waveguides

Light manipulations such as spin-direction locking propagation, robust transport, quantum teleportation and reconfigurable electromagnetic pathways have been investigated at the boundaries of photonic systems. Recently by breaking Dirac cones in time-reversal invariant photonic crystals, valley-pseudospin coupled edge states have been employed to realize selective propagation of light. Here, without photonic boundaries, we realize the propagation of pseudospin states in three-dimensional bulk metacrystal waveguides by employing the ubiquitous valley degree of freedom. Valley-dependent pseudospin bands are achieved in three-dimensional metacrystal waveguides without Dirac cones. Reconfigurable photonic valley Hall effect is proposed after studying the variation of pseudospin states near K' and K valleys. Moreover, a prototype of photonic blocker is realized by cascading two inversion asymmetric metacrystal waveguides in which the pseudospin direction locking propagation exists. In addition, valley-dependent pseudospin bands are also discussed in a realistic metamaterials sample. These results show an alternative way towards molding the pseudospin flow in photonic systems.

Quantum valley Hall effect and perfect valley filter based on photonic analogs of transitional metal dichalcogenides

We consider theoretically staggered honeycomb lattices for photons which can be viewed as photonic analogs of transitional metal dichalcogenides (TMD) monolayers. We propose a simple realization of a photonic Quantum Valley Hall effect (QVHE) at the interface between two TMD analogs with opposite staggering on each side. This results in the formation of valley-polarized propagating modes whose existence relies on the difference between the valley Chern numbers, which is a $\mathbb{Z}_2$ topological invariant. We show that the magnitude of the photonic spin-orbit coupling based on the energy splitting between TE and TM photonic modes allows to control the number and propagation direction of these interface modes. Finally, we consider the interface between a staggered and a regular honeycomb lattice subject to a non-zero Zeeman field, therefore showing Quantum Anomalous Hall Effect (QAHE). In such a case, the topologically protected one-way modes of the QAHE become valley-polarized and the system behaves as a perfect valley filter.

Photon Hall scattering from alkaline-earth-like atoms and alkali-like ions

We investigate the possibility of observing a magneto-transverse scattering of photons from alkaline-earth-like atoms as well as alkali-like ions and provide orders of magnitude. The transverse magneto-scattering is physically induced by the interference between two possible quantum transitions of an outer electron in a S state, one dispersive electric-dipole transition to a P orbital state and a second resonant electric-quadrupole transition to a D orbital state. In contrast with previous mechanisms proposed for such an atomic photonic Hall effect, no real photons are scattered by the electric-dipole allowed transition, which increases the ratio of Hall current to background photons significantly. The main experimental challenge is to overcome the small detection threshold, with only 10−5 photons scattered per atom per second.

Photonic versus electronic quantum anomalous Hall effect

We derive the diagram of the topological phases accessible within a generic Hamiltonian describing quantum anomalous Hall effect for photons and electrons in honeycomb lattices in presence of a Zeeman field and Spin-Orbit Coupling (SOC). The two cases differ crucially by the winding number of their SOC, which is 1 for the Rashba SOC of electrons, and 2 for the photon SOC induced by the energy splitting between the TE and TM modes. As a consequence, the two models exhibit opposite Chern numbers $\pm 2$ at low field. Moreover, the photonic system shows a topological transition absent in the electronic case. If the photonic states are mixed with excitonic resonances to form interacting exciton-polaritons, the effective Zeeman field can be induced and controlled by a circularly polarized pump. This new feature allows an all-optical control of the topological phase transitions.