Conventional magnetic-resonance-based wireless power transfer (WPT) relies on strong coupling between the transmitter and receiver, which imposes stringent constraints on transfer distance, operating frequency, and load matching, thereby limiting the simultaneous achievement of high efficiency and robustness. Here, we show that WPT enabled by non-Hermitian physics represents a fundamentally different resonance mechanism rather than a refinement of conventional schemes. By introducing a laterally coupled auxiliary resonator, the system is converted into a third-order non-Hermitian configuration, in which power transfer is governed by the eigenmode structure of an effective non-Hermitian Hamiltonian. A zero-reflection resonant mode emerges, associated with a topological phase vortex, ensuring a stable real-eigenfrequency operating point. As a result, efficient energy transfer is no longer restricted to the strong-coupling regime. High efficiency and robustness against variations in transfer distance and load impedance are simultaneously achieved even under weak coupling, while the operating frequency becomes tunable and can be shifted away from high-loss resonances to reduce standby power consumption. Theoretical and experimental results consistently confirm the non-Hermitian origin, topological stability, and practical advantages of the proposed scheme, establishing non-Hermitian physics as a new resonance paradigm for wireless power transfer.

High-precision optical sensing is fundamental to applications in biomedicine, environmental monitoring, and integrated photonics. A key challenge at the nanoscale is to combine strong field confinement with high spectral sensitivity, which conventional resonators or plasmonic platforms struggle to achieve due to broad linewidths and fabrication sensitivity. We propose a hybrid polaritonic structure where localized surface plasmon polaritons coherently couple to a Tamm plasmon polariton, giving rise to topological phase singularities. These singularities occur at near-zero reflectance, producing abrupt phase transitions and divergent phase sensitivity that far exceed amplitude-based sensing schemes. The platform further exhibits robustness against structural perturbations, such as positional shifts of embedded plasmonic defects. Our results demonstrate a compact, tunable, and topologically protected mechanism for refractive-index sensing, surpassing conventional surface plasmon resonance sensors and opening a route toward singularity-enhanced photonic devices.

The anomalies in light scattering associated with singularities are of great importance in both basic physics research and engineering applications. In this work, we focus on the coherent perfect absorption (CPA) singularities in an anti-parity-time (anti-PT) symmetric system and explore the coherent absorption characteristics of the system under various damping conditions. We theoretically and experimentally demonstrated CPA in both anti-PT symmetric phase and anti-PT symmetry broken phase, where dissipation plays a crucial role in the absorption efficiency of the system. Additionally, we theoretically observe pairs of CPA singularities with opposite topological charges, indicating the topological nature of the CPA in the anti-PT symmetric phase. We depict the movement of the zeros of the scattering matrix in the complex-frequency plane and the generation and annihilation processes of topological charges under different dissipative scenarios. Our work offers a promising platform for investigating non-Hermitian physics in open systems and provides valuable insights into the manipulation of electromagnetic waves in photonic systems.

One-dimensional topological Anderson insulators provide a paradigm for disorder-induced topological phases in which the underlying system turns from a trivial to a topological phase. It is widely recognized that the latter vanishes at large disorder amplitude. Here, and contrary to the general belief, we provide evidence for a successive disorder-driven topological transitions in a single-wall nanotube, culminating in a topological Anderson phase that remains unexpectedly robust at strong disorder. This phenomenon is confirmed by analysis of the corresponding topological invariant, which increases stepwise as disorder increases, giving evidence for the emergence of edge states. We experimentally implement these topological Anderson staircase phase transitions in a one-dimensional topolectrical circuit, where the persistence of edge states is revealed by node-voltage measurements. The robustness of the edge states is corroborated by numerical calculations of their localization properties. Our work opens the road to topological disordertronics, where topological phases can be tuned by disorder.

Significance High-sensitivity sensing is indispensable in information technology, biomedical diagnostics, and environmental monitoring, where the accurate detection of extremely weak perturbations often determines the performance and reliability of practical systems. Conventional Hermitian-based sensing platforms, such as frequency-shift sensors relying on resonance splitting, generally exhibit linear responses to external stimuli, which inherently limits their sensitivity under weak perturbations. As a result, they often struggle to meet the requirements for detecting nanoscale particles, weak biochemical interactions, or subtle environmental variations. To overcome these constraints, researchers turn their attention to new physical mechanisms beyond the Hermitian paradigm. Non-Hermitian systems, characterized by their energy exchange with the surrounding environment, introduce complex eigenvalue spectra and novel singular phenomena that are absent in closed Hermitian counterparts. In particular, exceptional points (EPs)-spectral degeneracies where eigenvalues and eigenvectors coalesce-enable square-root or nth-root scaling laws in response to perturbations. This unique nonlinear sensitivity enhancement has been experimentally validated across diverse platforms, including optical microcavities, photonic metasurfaces, acoustic resonators, and electronic circuits, highlighting the transformative potential of non-Hermitian singularities in redefining the sensitivity limits of modern sensors. Beyond the classical EP paradigm, non-Hermitian physics has expanded to encompass a broader family of singular mechanisms and topological effects that further enrich the landscape of sensing. Divergent exceptional points (DEPs) amplify perturbation responses beyond those of conventional EPs, while coherent-perfect-absorber?laser points (CPALPs) and linewidth suppression points (LSPs) provide new pathways for detecting weak phase shifts or nonlinear interactions with unprecedented accuracy. At the same time, non-Hermitian topological phenomena such as exceptional surfaces, edge-localized modes, and the non-Hermitian skin effect (NHSE) combine ultra-high sensitivity with inherent robustness against fabrication imperfections or environmental noise, thereby addressing one of the most critical bottlenecks in practical applications. These advances signify that non-Hermitian singularities are not merely theoretical constructs but powerful tools for engineering real-world sensors with both sensitivity enhancement and robustness. By leveraging the synergy between non-Hermitian physics and topological protection, researchers are paving the way toward next-generation sensing technologies capable of meeting the demanding requirements of photonics, acoustics, electronics, and wireless systems. Progress Early developments of non-Hermitian sensing are primarily centered on the exploration of second-order parity-time (PT) symmetric systems, where the coalescence of eigenvalues and eigenvectors at exceptional points produces a square-root response to external perturbations. Such systems have been experimentally demonstrated in a variety of photonic, acoustic, and electronic platforms, including optical microcavities, integrated microwave circuits, and mechanical resonators, each confirming the nonlinear scaling law and sensitivity enhancement over Hermitian counterparts (Figs. 1?2). In particular, the square-root dependence of mode splitting on perturbation strength allows the detection of nanoscale particles, stress, or refractive index changes with greatly amplified signals, establishing the fundamental advantage of EP-based sensing in realistic devices. These achievements lay the foundation for further advances toward higher-order and multifunctional singularity-enhanced sensing. Building upon these results, higher-order EPs have been investigated to realize cubic- and nth-root response laws, providing stronger sensitivity amplification in multi-resonator systems. Photonic molecules, PT-symmetric electrical circuits, and asymmetric scattering structures have been employed to demonstrate third-, fourth-, and even sixth-order EPs with pronounced nonlinear responses (Fig. 3). Such higher-order degeneracies extend the applicability of EP-based sensing to scenarios where weak perturbations must be detected under noisy or fluctuating environments, as the enhanced scaling laws magnify small signals without significantly degrading device functionality. In addition, flexible design platforms such as plasmonic systems and metamaterials allow the construction of arbitrary-order EPs, thereby providing greater freedom to optimize sensitivity across different frequency regimes. These developments show that EPs of various orders are not only theoretically tractable but also experimentally feasible, and they push the sensitivity frontier of non-Hermitian physics-inspired sensors. t In parallel, sensing mechanisms beyond EPs have been introduced to further enrich the landscape of non-Hermitian singularities. DEPs, CPALPs, hybrid EP-BIC states, and LSPs open new avenues for detecting weak phase perturbations and nonlinear interactions with enhanced sensitivity (Fig. 4). Furthermore, additional approaches based on external-field modulation, nonlinear response tuning, and noise-assisted detection (Figs. 5?6) further expand the design space, enabling flexible trade-offs between sensitivity and robustness. Finally, the combination of non-Hermitian and topological effects, such as exceptional surfaces and the NHSE, provides robust boundary-localized sensing platforms that are immune to bulk disorder yet highly sensitive to local perturbations (Figs. 7?8). The review culminates by showcasing practical applications of these mechanisms, including EP-based thermal imaging microscope slides, implantable wireless micro-sensors, and DEP-inspired hardware encryption devices (Fig. 9). Conclusions and Prospects In summary, non-Hermitian physics has provided powerful new mechanisms for realizing high-sensitivity sensing, going beyond the linear response limits of conventional Hermitian systems. Exceptional points and their higher-order extensions offer nonlinear scaling laws for signal amplification, while alternative singularities and topological effects introduce robustness against noise and structural imperfections. These advances not only validate the theoretical framework of non-Hermitian singularities but also establish practical routes toward multifunctional sensing applications. Looking ahead, further exploration of higher-dimensional structures, higher-order degeneracies, and hybrid mechanisms is expected to unlock broader opportunities for next-generation sensors with enhanced performance and robustness.

Strong disorder drives conventional Hermitian systems into Anderson insulating states, suppressing all topological phases. Here, we unveil symmetry-protected, anomalous topological phases in the strong disorder limit of a non-Hermitian system, characterized by a scale-invariant merging of zero-energy modes. Using the maximally symmetric Jx lattice as an ideal platform and introducing specifically engineered (ABBA-type) symmetry-preserving non-Hermitian disorder, we observe a sequence of disorder-induced phase transitions: from a trivial insulator into and through a non-Hermitian topological Anderson insulator (TAI) phase, culminating in a stable anomalous non-Hermitian TAI phase characterized by a quantized polarization Px approximate to 0.25. Within this anomalous phase protected by the mobility gap, the zero-energy modes exhibit a distinct (N/2)-mode coalescence that scales with system size. Our findings demonstrate that non-Hermitian disorder engineered to preserve symmetry can induce and protect novel topological order inaccessible to conventional Hermitian disorder, thereby advancing the fundamental understanding of topological phenomena mediated by the interplay of disorder and non-Hermiticity.

Herein, the photonic dispersion of metasurfaces is tailored via multiple Brillouin zone foldings (BZFs) to achieve robust ultrahigh-Q resonances and giant Goos-H & auml;nchen shifts (GHSs) with geometry-free and angle-insensitive properties. By introducing the geometric perturbation into the lattice, the guided resonances (GRs) lying below the radiative continuum are folded into the radiative continuum and evolve into BZF-induced guided mode resonances (BZF-GMRs) with ultrahigh Q factors. Remarkably, the Q factors of the BZF-GMRs maintain ultrahigh across a wide momentum space and exhibit ultralow sensitivity to the geometric shape of the scatterers, inherited from the intrinsic infinitely high Q factors of the GRs. More importantly, it is discovered that the Q factor of the BZF-GMR scales with the fourth power of the order of BZF. Leveraging these robust ultrahigh-Q BZF-GMRs, we realize giant geometry-free and angle-insensitive GHSs (on the scale of 103 lambda). Full-wave simulations are performed to demonstrate the enhancement of GHSs. This work not only reveals the relationship between BZF and GHS, but also offers a general route to achieving robust ultrahigh-Q resonances and giant GHSs.

The topological transition of polariton dispersion in twisted van der Waals layers at the photonic magic angle results in the diffraction-less and collimated propagation state, termed canalization regime. This type of robust transport of polaritons (i.e., polariton canalization) holds promise for subwavelength control of energy flows. However, the lack of in situ dynamic tunability of canalized polaritons hinders such control because the canalization direction is fixed in the fabricated device. Here, we overcome this limitation by demonstrating programmable polariton canalization in a reconfigurable single-layer metasurface. By engineering the orientation of metasurface unit cells, the direction of canalized magnetic polaritons can be programmed along any in-plane direction (i.e., dynamic all-angle tunability). On-demand steering of canalized polaritons allows customized near-field patterns to be obtained at any desired location-a proof of concept for canalization-based information display applications. These findings offer opportunities to transcend conventional diffraction constraints for integrated photonic devices, thus opening the door for photonic applications where on-demand control is crucial.

Coherent perfect absorption (CPA) has long been regarded as the time-reversed analogue of lasing, but its realization has been fundamentally constrained to steady-state interference under impedance-matching conditions. Here, we report the first experimental demonstration of transient CPA (TCPA), achieved by harnessing interference between a steady mode and a self-excited evanescent mode in a non-Hermitian resonant circuit. By shifting the focus from the frequency domain to the time domain, we uncover a new mechanism that enables perfect absorption in mismatched systems, thereby overcoming a key limitation of conventional CPA. We further show that TCPA can be systematically controlled through circuit switching, validated by theory, simulation, and experiment, and leveraged to establish a pulse-driven wireless power transfer (WPT) scheme. This approach sustains high transfer efficiency even in weak-coupling regimes, outperforming conventional steady-state and adaptive-frequency designs. Our results introduce a previously unexplored class of time-domain non-Hermitian interference, laying the foundation for dynamically reconfigurable wave systems and opening new avenues for efficient WPT, high-sensitivity sensing, and integrated photonic control.

Magnetic resonance wireless power transfer (WPT) with parity-time-(PT-) symmetry has been extensively studied due to its high transfer efficiency. However, conventional second-order PT-symmetric systems face several challenges in practical WPT applications. Due to near-field coupling, frequency splitting occurs in the strong coupling region, necessitating frequency tracking to maintain optimal transfer efficiency. Although the system can operate at a fixed frequency in the weak coupling region, the efficiency is significantly reduced. Strict PT-symmetry constraints also limit the system's flexibility in engineering applications. Additionally, severe field leakage from the transmitter coil in the strong coupling region leads to poor electromagnetic compatibility. Here, we demonstrate efficient WPT by implementing a bound state in the continuum (BIC) in a high-order non-Hermitian system based on a composite transmitter. BICs offer greater flexibility in practical applications as they do not require strict PT-symmetry. Remarkably, the optimized WPT system constructed with a composite transmitter maintains a stable pure real working frequency, reduces field leakage from the transmitter coil, and exhibits significant advantages over conventional second-order PT-symmetric systems. Our finding expands the application of BICs in high-efficiency WPT systems and provides a robust platform for realizing miniaturized and integrated high-order non-Hermitian WPT systems. BIC

Optical skyrmions, characterized by their unique topological field configurations and intrinsic stability, offer a transformative foundation for next-generation technologies. Besides fundamental studies often prioritized in skyrmion research, we focus on the distinctive multi-eigenfrequency characteristics and field distributions of skyrmion resonance modes within a non-Hermitian framework, leading to the creation of a integrated near-field platform that simultaneously delivers wireless power transfer, high-fidelity wireless communication, and precision wireless sensing. Crucially, this integrated approach overcomes key limitations in conventional near-field electromagnetic systems. The conflict of different applications within compact architecture and robust, high-effective method is satisfied by two synergistic mechanisms: 1) robust, multi-channel wireless communication inherently supported by the skyrmion resonant structure and 2) efficient power transfer and ultra-sensitive detection driven by exceptional point. This unprecedented integration directly addresses in demanding scenarios, such as minimally-invasive and implantable biomedical devices, where size constraints, functional complexity, and operational reliability are paramount. Our work not only advances fundamental understanding of controllable topological photonics but also demonstrates the remarkable versatility and practical utility of skyrmion-based architectures in complex real-world needs, establishing a novel paradigm for the development of highly integrated and robust near-field technologies.

Topological Anderson insulators provide a paradigm for disorder-induced topology, in which the underlying system turns from a trivial to a topological phase. It is widely recognized that the latter disappears at large disorder amplitude. Here, and contrary to the general belief, we provide evidence for successive disorder-driven topological transitions ending up in an unconventional topological Anderson phase that remains unexpectedly robust at strong disorder. The corresponding topological invariant increases stepwise with disorder, and then saturates in the strong-disorder regime, without reverting to a trivial Anderson insulator. We experimentally realize these topological Anderson staircase transitions in a one-dimensional topolectrical circuit that emulates single-wall nanotubes. Our work opens the road to topological disordertronics, in which robust topological phases can be tuned by disorder. Using a topolectrical circuit, the authors realise an unconventional disorder-tuned cascade of topological Anderson phase transitions ending up, contrary to the general belief, in an extremely robust topological phase. This work opens the gate for topological disordertronics, where topological channels can be tuned by disorder.

Topological wireless power transfer (WPT) technologies have attracted considerable interest due to their high transmission efficiency and robustness in coupled array configurations. However, conventional periodic and quasi-periodic topological chains exhibit limited adaptability in complex application scenarios, such as large-area simultaneous multi-load charging. In this work, we experimentally demonstrate a large-area topological defect state by constructing a gapless chain of uniformly coupled resonators at the interface of two topologically distinct Su-Schrieffer-Heeger (SSH) configurations. This topological defect state exhibits strong localization at multiple target sites, enabling efficient and concurrent wireless power delivery to spatially distributed loads. Furthermore, the unique wavefunction distribution enhances robustness against positional variations, ensuring stable energy transfer despite fluctuations in device placement. The proposed large-area topological framework offers fundamental insights into harnessing diverse topological states for advanced WPT applications, particularly in scenarios demanding spatial flexibility and multi-target energy delivery.

The formed optical cavity mode intensively relies on the size and geometry of optical cavity. When the defect or impurity exists inside the cavity, the formed cavity mode will be destroyed. Here, we propose a metacavity consisting of arrays of linear-crossing metamaterials (LCMMs) with abnormal dispersion, where each LCMM offers both the directional propagation channel for all incident angles and the negative refraction across its neighboring LCMMs. Such metacavity can be efficiently excited by a point source, where the excited wave vector components propagate along the same optical path in the cavity. More importantly, the proposed metacavity possesses the remarkable feature of partial defect immunity and geometry robustness. Assisted by two-dimensional transmission lines with loaded-circuit elements, a metacavity with partial defect immunity has been experimentally realized. Our work offers a new avenue for designing optical resonators excited by the point source in integrated photonics, which is very useful for high-efficiency filters, ultrasensitive sensors, and enhancement of light-matter interactions.

The rapid development of topological photonics has significantly facilitated the development of novel microwave and optical devices with richer electromagnetic properties.A stable and efficient guided wave is a necessary condition for optical information transmission and processing.However,most topological waveguides are confined at a domain wall around the interfaces and usually operate in a single-type topological mode,leading to low-throughput energy transmission over a single frequency band.Here,we propose,design,and experimen-tally demonstrate a novel planar microstrip heterostructure system based on topological LC circuits that supports a dual-type topological large-area waveguide state,and the system showcases tunable mode widths with different operating bandwidths.Inheriting from the pseudospin and valley topology,the topological large-area waveguides exhibit the pseudospin-and valley-locked properties at different frequency windows and have strong robustness against defects.Moreover,the large-area topological waveguide states of high-energy capacity channel intersec-tions and beam expanders with topological pseudospin and valley mode width degrees of freedom are verified numerically and experimentally.We also show the distinct topological origins of large-area topological waveguide states that provide versatile signal routing paths by their intrinsic coupling properties.Our system provides an efficient scheme to realize the tunable width and the multi-mode bandwidth of topological waveguides,which can further promote the applications of multi-functional high-performance topological photonic integrated circuit systems in on-chip communication and signal processing.

Traditional resonant sensors are often constrained by low quality-(Q-) factors and impedance mismatches, which severely limit their precision and sensitivity. In this study, we introduce an approach that leverages transient reflectionless phenomena within a simple open single-resonator system. Unlike conventional steady-state responses, which typically exhibit a single reflection peak, our method exploits transient responses to generate multiple reflection extrema, significantly enhancing the reflection contrast. Experimental and theoretical results demonstrate that this approach increases the reflection contrast by 67% in systems with a Q-factor of approximately 5. By enabling multiple high-contrast reflection extrema without the need for additional control mechanisms, our method overcomes the limitations imposed by low Q-factors and impedance mismatches. This breakthrough not only improves measurement precision and robustness but also paves the way for high-precision non-Hermitian sensing in applications such as information processing, environmental monitoring, and precision measurement. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Magnetic resonance wireless power transfer (WPT) has emerged as a pivotal technology for near-field electromagnetic manipulation, enabling wire-free energy delivery across diverse applications ranging from consumer electronics and implantable medical devices to electric vehicles. While near-field coupling facilitates this paradigm shift, it imposes inherent constraints: the exponential decay of coupling strength fundamentally limits transfer distance to short-to-mid ranges, and complex power delivery pathways—exemplified by robotic arms—necessitate relay coils configured in domino-like arrays. Conventional domino architectures, however, suffer from significant drawbacks including detrimental frequency splitting due to multi-coil near-field coupling, exacerbated system losses under load, and an inherent lack of precise spatial control over energy delivery. To overcome these limitations, we introduce a customized WPT paradigm based on a one-dimensional non-Hermitian chain with engineered iso-spectral modulation. Through precise control of inter-resonator coupling strengths following a parabolic profile, we achieve an equally spaced eigenvalue spectrum. Crucially, frequency-selective excitation enables deterministic and customized energy localization at predetermined sites within the chain. This approach not only provides a novel platform for developing advanced WPT systems, particularly for simultaneous multi-target energy delivery, but also deepens the fundamental understanding of complex energy transfer dynamics governed by tailored coupling and non-Hermitian physics.

For many modern photonics applications, significant nonlinear optical interactions are crucial. However, achieving this typically demands powerful laser sources and extended interaction area because most natural materials exhibit extremely weak optical nonlinearities. Hence, integrating nonlinear optics into novel nanophotonics devices poses a challenge. In this work, an asymmetrical optical nonlinear metasurface is proposed that combines effective zero-index media with bound states in the continuum (BIC). This scheme enables us to achieve a huge non-reciprocal intensity range of approximate to 7.1, leveraging significantly enhanced optical nonlinear effects. The high-Q characteristics of quasi-BIC within the zero-index background greatly enhance light-matter interactions and reduce operational power requirements. The non-reciprocal metasurface relies on a straightforward set of material requirements and fabrication processes, making it a highly versatile option for various applications in optical communication, light detection, signal processing.

Omnidirectional perfect transparency (OPT) in materials is very useful in many applications. Traditional systems face challenges in achieving OPT owing to the fact that the propagating phase changes with the incident angles. Previous methods of realizing OPT are constrained by complex electromagnetic interactions and restricted to a single frequency, which limits the applications of OPT. In this study, inspired by the field of twistronics in photonics, we propose a twisted structure composed of alternating two kinds of tilted anisotropic metamaterials (TAMs), with the optical axis rotated in opposite directions to realize broadband OPT. These TAMs are effectively obtained by rotating multilayers composed of two kinds of deep-subwavelength dielectric through equal angles in opposite directions. As the incident angles increase, the variations of the propagating phases in the two kinds of TAMs are opposite. This phase variation compensation effect makes the total propagating phase in the structure angle-independent, leading to the omnidirectional zero-reflectance resonance at a given frequency. Moreover, because of the dispersionless dielectrics, OPT can occur at multiple zero-reflectance resonance frequencies in a broad transmission band. The broadband OPT can be flexibly designed at various frequency ranges. As a proof of concept, we fabricate a twisted structure and experimentally demonstrate broadband OPT in the microwave range. Our work not only explores a physical method to realize broadband OPT in a low-loss and feasible platform but also has many potential applications in optical systems and photonic devices.