The interaction of light with correlated quantum matter in two-dimensional (2D) materials offers a powerful platform for exploring emergent quantum phenomena. Here, we report the realization of Landau polaritons in a monolayer tungsten diselenide (WSe_{2}) integrated into an optical microcavity. By embedding a two-dimensional electron gas (2DEG) in the monolayer and applying a perpendicular magnetic field, we achieve strong coupling between cavity photons and interband Landau level (LL) transitions, giving rise to hybrid light-matter quasiparticles. These Landau polaritons exhibit valley-dependent oscillations in the coupling strengths and resonance energies, driven by the electrical and magnetic filling of valley-contrasting Landau levels. Moreover, intervalley correlations between LL transitions and opposite-valley electrons lead to nonlinear renormalization of both LL transition energies and Landau-polariton coupling strengths. Our results establish a new paradigm for cavity quantum electrodynamics in correlated 2D systems and demonstrate control of Landau polaritons via the valley degree of freedom, opening new avenues for light-mediated manipulation of quantum phases.

Exceptional Points (EPs) are spectral singularities in non-Hermitian systems where eigenvalues and eigenvectors simultaneously coalesce. Manipulating EPs in solid-state systems typically requires complex architectures. Here, based on a hybrid system consisted of few layer rhenium disulfide (ReS 2 ) deposited on a distributed Bragg mirror, we demonstrate an all optical method to dynamically control EPs by harnessing the intrinsic optical anisotropy of ReS 2 . By utilizing the incident polarization angle as a dynamic control parameter, we continuously modulate the exciton-photon coupling strength, driving the system from the strong coupling regime to the weak coupling regime. The EPs is manifested as simultaneous coalescence of the real (energy) and imaginary (linewidth) parts of the complex eigenvalues. This dual-degeneracy provides unambiguous experimental evidence for EPs formation and the associated collapse of the Hilbert space dimensionality. Our findings establish anisotropic light-matter coupled system as a robust paradigm for exploring non-Hermitian topology in photonics, enabling polarization driven topological devices without intricate nanofabrication.

The optical spin Hall effect (OSHE), resulting from photonic spin-orbit coupling, has become a pivotal phenomenon in nanophotonics. While a tunable optical spin Hall effect has been achieved in liquid-crystal-based anisotropic microcavities, a more general material-independent and broadband platform remains to be explored. In this work, we demonstrate dynamic manipulation on optical spin currents in an open cavity, where the strength and direction of the effective magnetic field experienced by photons can be precisely controlled. By exploring the cavity length dependence of the TE-TM mode splitting and photonic spin pattern both experimentally and theoretically, we unambiguously reveal the mechanism that governs the tunable OSHE. This approach relies on the intrinsic polarization properties of planar cavity modes, and is applicable for photonic spin control in any hybrid light-matter system within a broad optical bandwidth.

Spin-decoupled metasurfaces hold significant potential for integrated photonics by enabling independent manipulation of the spin degree of freedom of light. However, achieving robust spin-decoupled performance over both a broad bandwidth and a wide range of incident angles remains a pivotal challenge. In this work, a spin-decoupled strategy incorporating the propagation phase with the geometric phase is implemented to design plasmonic metasurfaces capable of independently controlling wave fronts of orthogonally circularly polarized light in the visible spectrum. Two representative devices demonstrate distinct spin-decoupled functionalities: one generating a vortex beam under left circular polarization (LCP) and the other enabling LCP-selective bifocusing, while both maintain specular reflection under right circular polarization. Systematic experimental characterization using microscopic spectroscopy demonstrates robust spin-decoupled performance across an 80 nm bandwidth and a wide range of incident angles with a scanning range of up to 40 & micro;m. This dual advantage in spectral and angular stability, surpassing typical dielectric counterparts, provides solutions for reliable metasurface devices in applications such as multiplexed optical communications and miniaturized high-resolution imaging.

The ability to arbitrarily control the polarization state of holographic images remains crucial in optical information technology. Current metasurface-based holography largely produces fixed polarization outputs, limiting its utility in polarization-encoded applications. Here, we present a spin-decoupled metasurface that enables programmable polarization tailoring of holographic outputs through independent phase control of circular polarization channels. By engineering specific phase differences between left- and right-handed circularly polarized light, we demonstrate holograms whose output polarization can be continuously varied relative to the linear input. As a proof of concept, we fabricate metasurfaces that reconstruct four distinct holographic letters ("M", "E", "T", and "A"), each exhibiting a prescribed output linear polarization shift (0°, 45°, 90°, or 135°) under identical incident polarization. The devices operate across a broad bandwidth (700-1030 nm) and remain functional over a wide incident angular range from -20∘ to +20∘, while maintaining high fidelity under variations in input polarization. This approach provides a versatile platform for polarization-engineered holography, opening avenues for dynamic optical encoding, anti-counterfeiting, and secure displays.

Light inherently possesses multiple degrees of freedom (DoFs), such as wavelength, polarization, phase, and intensity, making it a powerful carrier for information encoding and processing. The accurate detection and analysis of these DoFs of light form the cornerstone of modern optics and photonics. With the rapid advancement of photonic integration technologies, integrated light field sensors have garnered significant attention for their potential to enable compact, multifunctional, and high-performance optical systems. Recent progress in nanophotonic architectures and computational perception has propelled the development of on-chip sensors capable of low- and high-dimensional light field measurements. This review focuses on recent advances in integrated optical sensors for spectra, polarization, and orbital angular momentum detection. The high-dimensional light field sensing includes spectral imaging, polarimetric imaging, phase imaging, spectropolarimetric detection, and polarized vortex beam detection. We systematically summarize the underlying physical mechanisms, engineering strategies, and representative device architectures, while also discussing their potential applications across various fields. Finally, we outline the existing challenges and offer a perspective on the future directions of chip-scale light field sensing technologies.

The emergence of the Abrikosov lattice in the normal phase of type-II superconducting films as the magnetic field approaches the critical field H_{c2} from above was predicted in Glatz et al. [Fluctuation spectroscopy of disordered two-dimensional superconductors, Phys. Rev. B 84, 104510 (2011)PRBMDO1098-012110.1103/PhysRevB.84.104510]. In the quantum fluctuation regime [Galitski and Larkin, Superconducting fluctuations at low temperature, Phys. Rev. B 63, 174506 (2001)PRBMDO0163-182910.1103/PhysRevB.63.174506], it is characterized by the formation of relatively large (ξ_{QF}∼ξ_{BCS}/sqrt[h[over ˜]], h[over ˜]=H/H_{c2}-1) and long-lived (τ_{QF}∼τ_{Δ}/h[over ˜], τ_{Δ}=ℏ/Δ) clusters of rotating fluctuation Cooper pairs, representing precursors of Abrikosov vortices. We show that these fluctuation-induced vortex clusters can be detected through their high-frequency electromagnetic response. Specifically, they produce a pronounced enhancement of the imaginary part of the ac conductivity at characteristic frequencies ω_{QF}∼h[over ˜]/τ_{Δ}, arising directly from quantum fluctuations, being well below the superconducting threshold at 2/τ_{Δ}. For niobium, ω_{QF} falls within the experimentally accessible microwave range, making this effect directly testable using modern microwave spectroscopy.

Exceptional points(EPs)are spectral singularities in non-Hermitian systems where eigenvalues and eigenvectors simultaneously coalesce.Manipulating EPs in solid-state systems typically requires complex architectures.Here,based on a hybrid system consisted of few-layer rhenium disulfide(ReS2)deposited on a distributed Bragg mirror,we demonstrate an all-optical method to dynamically control EPs by harnessing the intrinsic optical anisotropy of ReS2.By utilizing the incident polarization angle as a dynamic control parameter,we continuously modulate the exciton-photon coupling strength,driving the system from the strong coupling regime to the weak coupling regime.The EPs are manifested as simultaneous coalescence of the real(energy)and imaginary(linewidth)parts of the complex eigenvalues.This dual-degeneracy provides unambiguous experimental evidence for EP formation and the associated collapse of the Hilbert space dimensionality.Our findings establish anisotropic light-matter coupled systems as a robust paradigm for exploring non-Hermitian topology in photonics,enabling polarization-driven topological devices without intricate nanofabrication.

The Coulomb focusing effect on different sub-laser-cycle electrons, i.e., prepeak direct and postpeak rescattering electrons, is theoretically investigated using the exact solution of three-dimensional (3D) time-dependent Schr & ouml;dinger equation (TDSE), as well as semiclassical simulations based on both adiabatic and nonadiabatic models in the orthogonally polarized two-color laser field. By comparing their photoelectron momentum distributions (PMDs) along the light-propagation direction, we find that the nonadiabatic tunneling effect plays a critical role in modulating the relative strength of the Coulomb focusing between the direct and rescattering electrons, showing a pronounced phase dependence. Remarkably, within a specific phase window, this relative strength even reverses, leading to an abnormal behavior where the direct electrons experience stronger Coulomb focusing. Resorting to component-separated nonadiabatic models, we successfully uncover its underling dynamic mechanisms. We further demonstrate that this abnormal behavior can be clearly extracted from the TDSE-calculated PMD, paving the way for its direct experimental detection.

The photonic flat band, defined by minimal dispersion and near-zero group velocity, has facilitated significant advances in optical technologies. The practical applications of flat bands, such as enhanced light-matter interactions, require efficient coupling to far-field radiation. However, achieving controlled coupling between flat bands and their corresponding localized modes with far-field radiation remains challenging and elusive. Here, we achieve the tunable far-field excitation of a flat band in the near-infrared spectral range by coupling it to a photonic anapole mode. Distinct from conventional multipolar resonances in both its physical nature and unique radiation dynamics, the anapole mode offers highly localized field distributions and tunable emission characteristics, enabling the realization of a photonic flat band and precise control over its transition from a nonradiative to a radiative state. We directly observed the flat band within ±25° experimentally by angle-resolved far-field transmissivity spectroscopy. Simulation results extending to 90° confirm the persistence of the band's flatness across all incident angles, validating the inherent flatness of the band. Our findings not only provide a viable approach to accessing photonic flat bands but also significantly advance the field of nanoscale photonic manipulation, offering broad potential applications in optical technologies.

The recently observed strong-field photoelectron holographic pattern, 'the spiral', is considered as an ideal structure for target probing and the resolution of ultrafast dynamics. This intracycle interference pattern evolves into a carpet-like structure in multicycle laser pulses and is too indistinguishable in the photoelectron momentum distribution to be directly employed as a holographic tool. Using a semiclassical quantum-trajectory Monte Carlo model, we provide a laser field scheme for visualization of the spiral by adding a weak 1600 nm circularly polarized field to the 800 nm linearly polarized fundamental field. The results are verified by solving the time-dependent Schr & ouml;dinger equation. Furthermore, by combining the variation of the relative phase between the two colors with the rotation direction of the circularly polarized field, we achieved the precise manipulation of the fringe direction of the spiral. Our investigation shows that these are based on the modulation of the proportion of the spiral produced in each single laser cycle, rather than that of the birth time difference between the two types of rescattering electrons that form the spiral.

The emergence of the Abrikosov lattice in the normal phase of type-II superconducting films when the magnetic field approaches the critical field H_c2 from above was predicted in Ref. . In the quantum fluctuation regime it is characterized by the formation of relatively large (with sizes of order ξ_QF∼ ξ_BCS√(H_c2/(H-H_c2))) “long lived” (lifetime of order τ_QF∼ħ Δ^-1 H_c2/(H-H_c2)) clusters of rotating fluctuation Cooper pairs - signatures of developing Abrikosov vortices. We demonstrate that these fluctuation-induced vortex clusters, previously considered unobservable due to their ultrafast dynamics and weak (only logarithmically singular) contribution to the dc-conductivity, can in fact be detected through their distinct electromagnetic signature. By analyzing the high-frequency electromagnetic response of these rotating fluctuation Cooper pairs above the second critical field in superconducting film, we predict a pronounced and measurable enhancement in the imaginary part of the ac-conductivity arising directly from quantum fluctuations. This enhancement is expected to occur at characteristic frequencies ω_QF∼ħ^-1Δ(H-H_c2)/H_c2, which are well below the superconducting threshold at 2ħ^-1Δ, where a similar increase in imaginary conductivity occurs in the superconducting phase. For niobium, a prototypical type II superconductor, ω_QF lies in the experimentally accessible microwave range, making the effect directly testable with modern microwave spectroscopy.

Transition metal dichalcogenide moiré superlattices host rich correlated electronic states with high tunability. Their integration with optical cavities offers a new platform to explore hybrid light-matter interactions. However, the interplay between electron correlations and polariton formation remains uncharted. Here, we demonstrate the realization of a Mott insulator polariton in a gate-tunable MoSe2/WS2 moiré heterostructure embedded in a microcavity at the moiré lattice filling of ν = 1. A silver top layer was used to gate the moiré lattice and form the cavity reflection layer. Magnetic field studies indicate that the polaritons inherit valley Zeeman splitting from the moiré excitons, exhibiting saturation behavior similar to that of the bare moiré excitons. Our work establishes moiré polaritons as an electrically and magnetically tunable platform for engineering the quantum phases of light and matter.

Exciton-polaritons perform as ideal carriers of macroscopic quantum coherence, which can be potentially manipulated through precisely shaping the driving laser field. However, the connection of the coherence properties between the pumping laser and the strongly coupled light-and-matter system is studied to a lesser extent. In this paper, we visualize the femtosecond dynamics of coherence transfer from the driving laser field to the resonantly excited exciton-polariton by an interferometric measurement. The resonant polaritons can effectively preserve the coherence of the pumping laser field in femtosecond timescales. At a high excitation strength, non-resonant polaritons appear at higher energies delayed by several picoseconds, without the phase coherence from the pump, which is understood by a coupled oscillator model. Our results offer the possibility of regulating the polariton coherence by finely shaping the external pump laser fields.

Exciton-polaritons, formed by the strong coupling between excitons and photons, have been widely explored in monolayer transition metal dichalcogenides. However, the study has been limited to the materials with a bandgap at visible wavelengths, and devices working at telecom wavelengths remain largely unexplored. Here, we report exciton polaritons based on a monolayer of MoTe2 integrated with a planar cavity consisting of silver mirrors. An all-dry transfer method is applied to keep the air-sensitive monolayer, MoTe2, pristine. Moreover, we implement the angle-resolved spectroscopy on the device using the Fourier lens scanning method based on a line-array camera. Thanks to the large coupling strength of the exciton and the small mode volume of the cavity, the strong coupling persists up to 200 K. Our findings open up new possibilities for exploring polariton physics at telecom wavelengths and potential integration with optical fiber communication systems.

Van der Waals semiconductors have provided a new platform to extend the physics and applications of cavity exciton polaritons, thanks to their flexibility of integration, large oscillator strength, and novel moir & eacute; physics. However, the inhomogeneous broadening of excitons, originating from strain, defect, or interface fluctuation, has been an obstacle to further exploring coherent quantum phenomena and devices in this community. In this work, we show that the contribution of exciton inhomogeneous broadening to polariton linewidth can be fully suppressed by increasing Rabi splitting. The results can be well reproduced theoretically- by modeling the excitonphoton coupling using a non-Hermitian Hamiltonian. Our findings not only shed light on the development of coherent Van der Waals polariton devices but also demonstrate a general conclusion on the correlation between the inhomogeneous broadening of a solid-state oscillator and the linewidth of its corresponding light-matter hybrids.

Two-dimensional transition metal dichalcogenide heterostructures provide a unique opportunity for quantum engineering of electronic and excitonic states at the nanoscale. Critical optical properties of interlayer excitons, including transition energy, optical selectivity, and quantum yield, are strongly correlated to the stacking orders. However, these optical properties could vary from sample to sample, setting an obstacle to extracting the intrinsic stacking order dependence experimentally. We report an effective method to fabricate heterobilayers with both stacking orders obtained on a single device. The sharp difference of interlayer excitons induced by the stacking orders was unambiguously identified, including emission wavelength, valley polarization, and temperature dependence of quantum yield. This method provides a flexible platform to study stacking order dependence of heterobilayer excitons, and can be readily applied to explore the layer hybridization, strong correlations, and exciton diffusion that are sensitive to stacking order.

Exciton polaritons-quasi-particle excitations consisting of strongly coupled photons and excitons-present fascinating possibilities for photonic circuits, owing to their strong nonlinearity, ultrafast reaction times and their ability to form macroscopic quantum states at room temperature via non-equilibrium condensation. Past implementations of transistors and logic gates with exciton polaritons have been mostly realized using the spatial propagation of polariton fluids, which place high demands on the fabrication of the microcavities and typically require complex manipulations. In this work we have implemented the full set of logical gate functionalities (that is, temporal AND, OR and NOT gates) in localized exciton polaritons at room temperature, on the basis of precisely controlling the interplay between polariton condensate and exciton reservoir dynamics, using a two-pulse excitation scheme. The dynamics intrinsically covers the cascadability required by the logical operations, enabling efficient information processing without the need for spatial flow. The temporal polariton logic gates demonstrate advantages in ultrafast switching, universality and simplified compatibility with other dimensional controls, showing great potential for building polariton logic networks in strongly coupled light-matter systems.