Abstract We present a theoretical study demonstrating that the photonic spin Hall effect (PSHE) can be both actively tuned and greatly amplified by exploiting the nonlocal, nonlinear optical response of a strongly interacting Rydberg gas operating under electromagnetically induced transparency. Rather than relying on fixed phase metasurfaces or conventional Kerr materials, long range interactions between Rydberg atoms create a spatially extended, intensity dependent refractive index profile that enables dynamic spin resolved beam deflection. In a glass–Rydberg–glass trilayer model, we show that the PSHE displacement can be varied smoothly in magnitude and even reversed in sign by adjusting atomic density, probe intensity, laser detunings, and interaction strength. This nonlocal nonlinearity transforms the typically weak PSHE into a macroscopically observable and dynamically controllable effect. Our results establish a versatile platform for reconfigurable spin-dependent photonic control, with potential applications in high-sensitivity optical metrology, spin-based beam steering, and tunable quantum-optical information processing.
Abstract We present a theoretical study demonstrating that the photonic spin Hall effect (PSHE) can be both actively tuned and greatly amplified by exploiting the nonlocal, nonlinear optical response of a strongly interacting Rydberg gas operating under electromagnetically induced transparency. Rather than relying on fixed phase metasurfaces or conventional Kerr materials, long range interactions between Rydberg atoms create a spatially extended, intensity dependent refractive index profile that enables dynamic spin resolved beam deflection. In a glass–Rydberg–glass trilayer model, we show that the PSHE displacement can be varied smoothly in magnitude and even reversed in sign by adjusting atomic density, probe intensity, laser detunings, and interaction strength. This nonlocal nonlinearity transforms the typically weak PSHE into a macroscopically observable and dynamically controllable effect. Our results establish a versatile platform for reconfigurable spin-dependent photonic control, with potential applications in high-sensitivity optical metrology, spin-based beam steering, and tunable quantum-optical information processing.
Abstract The photonic spin Hall effect (SHE) is explored in a highly tunable Rydberg‐based atomic system by leveraging the distinctive properties of Rydberg superatoms. These superatoms arise from strong dipole–dipole interactions and extended radiative lifetimes, resulting in collective excitations governed by the dipole blockade mechanism. An ensemble of three‐level atoms in a cascade configuration models a medium in which each superatom acts as a coherent quantum entity. The photonic SHE shows strong dependence on the probe field Rabi frequency and atomic number density. At high Rabi frequencies, the blockade effect suppresses the photonic SHE, confining its occurrence to specific resonant conditions. In contrast, under weak probe excitation, the blockade influence diminishes, enabling an amplified photonic SHE response at resonant detuning due to increased light‐matter interaction sensitivity. Reducing atomic number density further broadens the detuning range over which the photonic SHE occurs, indicating a transition toward a more sensitive, less resonance‐constrained optical behavior. The effect of van der Waals interactions on the photonic SHE shift is also characterized. This expanded operational bandwidth demonstrates the potential of Rydberg‐based systems for robust spin‐optical control, particularly in scenarios where precise stabilization of the probe field frequency is experimentally challenging.
Abstract The Photonic spin Hall effect (PSHE) offers fundamental insights into spin–orbit interactions of light, yet its control over compact, tunable platforms remains a challenge. Here, we investigate the PSHE in a solid-state platform of N -coupled quantum dots (CQDs), focusing on both the linear absorption and Kerr nonlinear regimes. On this platform, an external electric field controls electron tunneling between CQDs, resulting in multiple tunneling-induced transparency windows. We report a giant enhancement of the Kerr nonlinearity, achieving orders-of-magnitude increases while suppressing linear absorption—a domain that is favorable for low-power nonlinear photonics. Exploiting this, we demonstrate that the PSHE shift can be drastically enhanced and controlled by tuning the excited-state transition frequency and tunneling strengths, which significantly modify the Brewster angle. This active nonlinear control improves static nanostructures by combining the tunability of atomic systems with the functionality of an integrable quantum material. Our results establish N -CQDs as a viable platform for producing giant Kerr nonlinearity-driven PSHE, opening up new possibilities for tunable low-power spin–orbit light control in quantum photonics.
We theoretically investigate the transverse photonic spin Hall effect (PSHE) in a cavity structure containing a double-tripod (DT) atomic medium. We show that the internal topology of the double-tripod system can be coherently reconfigured through the relative phase of the control fields and the two-photon detuning, leading to qualitatively distinct effective configurations. These structural transformations reshape the transparency bandwidth, absorption spectrum, and dispersive slope, which in turn govern the spin-dependent reflection phase responsible for the PSHE. We demonstrate that large transverse shifts emerge in low-loss dispersive windows and are strongly enhanced near the Brewster angle due to the sensitive dependence of the reflection phase on the optical response. The magnitude, spectral range, and even sign of the spin-dependent displacement can be reversibly tuned by adjusting the phase, detuning, and atomic density. Our results reveal that cavity-assisted DT media provide a reconfigurable platform in which internal quantum interference directly maps to controllable spin–orbit photonic transport.
The photonic spin Hall effect (PSHE), a result of spin-orbit interaction, has attracted significant interest because of its fundamental importance and potential applications. Optical losses are ubiquitous, which inherently suppress the photonic spin Hall shift (PSHS). In this work, we consider an atomic medium that exhibits both absorption and transparency to investigate and mitigate the effects of loss on PSHS. We demonstrate that laser-induced coherence in an atomic medium, leading to electromagnetically induced transparency (EIT) at resonance, counteracts the detrimental effects of losses on the PSHS. Upon EIT in a coherent medium enclosed within dielectric slabs, the reflectivity of the incident polarized state is reduced near Brewster's angle to enhance PSHS. Moreover, the tunable refractive index of the atomic medium enables the manipulation of PSHS without structural modifications with a tiny loss. Our proposed loss-free approach to PSHS may enable advanced optical sensing and other spin-based applications.
X waves are a special type of wave packet that can maintain their transverse profile of X shape during propagation, and they are of much interest for the study of fundamental physics and practical applications. Here we present a scheme to generate nonlinear X waves and realize their active control by using a cold gas of Rydberg atoms via electromagnetically induced transparency (EIT). We show that, due to the EIT effect contributed by a control laser field and the strong, nonlocal Kerr nonlinearity contributed by Rydberg-Rydberg interaction between atoms, the system supports high-dimensional, nonlocal, and nonlinear optical X waves, which have low propagation loss, ultraslow propagation velocity, and ultralow generation power. We also show that the stability domain of such X waves can be greatly enlarged by increasing the nonlocality degree of the Kerr nonlinearity, and their motion trajectory can be manipulated by using an external magnetic field. Our study opens a route for generating and controlling nonlocal ultraslow nonlinear optical X waves, which may have promising applications in optical information processing and transmission.
Abstract Rydberg atoms, characterized by their giant polarizability and strong long-range interactions, provide an ideal platform for exploring optical nonlinearities. By coupling light to ensembles of Rydberg atoms, one can map the strong and nonlocal interactions between Rydberg atoms and light fields. A particularly important scheme for realizing such nonlinearity is electromagnetically induced transparency (EIT). This article presents a review of the research progress in nonlinear optics based on Rydberg-EIT systems, particularly nonlinear light propagation in Rydberg atomic gases. We first introduce the fundamental properties of Rydberg atoms and the physical mechanism of EIT-enhanced nonlinearity, emphasizing how the Rydberg blockade effect endows the system with a giant nonlocal Kerr nonlinearity. Subsequently, we discuss some typical nonlinear optical phenomena in such a system with focusing and defocusing nonlocal nonlinearities. In the focusing regime, we discuss spatial solitons, vortex solitons, soliton cloning, soliton molecules, optical bullets, and self-induced transparency solitons. Other topics are also discussed. In the defocusing regime, we analyze pattern formation and shock wave dynamics. Finally, we provide an outlook on the future development of this field toward quantum control, hybrid-system integration, and novel functional devices.