Robust multi-mode rainbow trapping with ultra-high-Q Fano resonances.

We present a groundbreaking and versatile approach to multi-mode rainbow trapping in photonic crystal waveguides (PCWs), overcoming long-standing limitations in photonic device design. Our innovative semi-bilayer PC design, formed by stacking two PCs, enables the realization of new photonic modes that were previously inaccessible, leading to enhanced device flexibility, improved performance, and increased resilience to defects and imperfections. By meticulously engineering a chirped PC within the PCW, we achieve multi-mode light trapping at distinct positions for different frequencies along the waveguide, effectively creating a rainbow of light. This study paves the way for efficient and robust trapping and demultiplexing of multiple wavelengths, opening up new avenues for on-chip nanophotonic applications. Moreover, the realization of ultra-high-quality (Q) factor Fano resonances within the waveguide cavity unveils unprecedented possibilities for designing on-chip nanophotonic devices. The diverse array of Fano resonances holds immense potentials for developing novel optical filters, switches, and lasers with exceptionally low thresholds. Our proposed structure offers a more compact, efficient, and robust solution for multi-wavelength photonic device applications.

Topological rainbow based on coupling of topological waveguide and cavity.

Topological photonics and topological photonic states have opened up a new frontier for optical manipulation and robust light trapping. The topological rainbow can separate different frequencies of topological states into different positions. This work combines a topological photonic crystal waveguide (topological PCW) with the optical cavity. The dipole and quadrupole topological rainbows are realized through increasing cavity size along the coupling interface. The flatted band can be obtained by increasing cavity length due to interaction strength between the optical field and defected region material which is extensively promoted. The light propagation through the coupling interface is built on the evanescent overlapping mode tails of the localized fields between bordering cavities. Thus, the ultra-low group velocity is realized at a cavity length more than the lattice constant, which is appropriate for realizing an accurate and precise topological rainbow. Hence, this is a novel release for strong localization with robust transmission and owns the possibility to realize high-performance optical storage devices.

Computer-Aided Design of DNA Self-Limited Assembly for Relative Quantification of Membrane Proteins.

Immunofluorescence imaging of cells plays a vital role in biomedical research and clinical diagnosis. However, when it is applied to relative quantification of proteins, it suffers from insufficient fluorescence intensity or partial overexposure, resulting in inaccurate relative quantification. Herein, we report a computer-aided design of DNA self-limited assembly (CAD-SLA) technology and apply it for relative quantification of membrane proteins, a concept proposed for the first time. CAD-SLA can achieve exponential cascade signal amplification in one pot and terminate at any desired level. By conjugating CAD-SLA with immunofluorescence, in situ imaging of cell membrane proteins is achieved with a controllable amplification level. Besides, comprehensive fluorescence intensity information from fluorescent images can be obtained, accurately showing relative quantitative information. Slight protein expression differences previously indistinguishable by immunofluorescence or Western blotting can now be discriminated, making fluorescence imaging-based relative quantification a promising tool for membrane protein analysis. From the perspectives of both DNA self-assembly technology and immunofluorescence technology, this work has solved difficult problems and provided important reference for future development.

Topological polarization selection concentrator.

Topological polarization selection devices, which can separate topological photonic states of different polarizations into different positions, play a key role in the field of integrated photonics. However, there has been no effective method to realize such devices to date. Here, we have realized a topological polarization selection concentrator based on synthetic dimensions. The topological edge states of double polarization modes are constructed by introducing lattice translation as a synthetic dimension in a completed photonic bandgap photonic crystal with both TE and TM modes. The proposed device can work on multiple frequencies and is robust against disorders. This work provides a new,to the best of our knowledge, scheme to realize topological polarization selection devices, and it will enable practical applications such as topological polarization routers, optical storage, and optical buffers.

Gain-Loss-Induced Hybrid Skin-Topological Effect.

Non-Hermitian topological effects are of crucial importance both in fundamental physics and applications. Here we discover the gain-loss-induced hybrid second-order skin-topological effect and the PT phase transition in skin-topological modes. By studying a non-Hermitian Haldane model, we find that the topological edge modes are localized on a special type of corner, while the bulk modes remain extended. Such an effect originates from the interplay between gain, loss, and the chiral edge currents induced by the nonlocal flux, which can be characterized by considering the properties of the edge sites as a one-dimensional chain. We establish a relation between the skin-topological effect and the PT symmetries belonging to different edges. Moreover, we discover the PT phase transition with the emergence of exceptional points between pairs of skin-topological modes. Our results pave the way for the investigation of non-Hermitian topological physics and PT phase transition in higher-dimensional systems.

Effective Hamiltonian for Photonic Topological Insulator with Non-Hermitian Domain Walls.

The gain and loss in photonic lattices provide possibilities for many functional phenomena. In this Letter, we consider photonic topological insulators with different types of gain-loss domain walls, which will break the translational symmetry of the lattices. A method is proposed to construct effective Hamiltonians, which accurately describe states and the corresponding energies at the domain walls for different types of photonic topological insulators and domain walls with arbitrary shapes. We also consider domain-induced higher-order topological states in two-dimensional non-Hermitian Aubry-André-Harper lattices and use our method to explain such phenomena successfully. Our results reveal the physics in photonic topological insulators with gain-loss domain walls, which provides advanced pathways for manipulation of non-Hermitian topological states in photonic systems.

Single-Cell Analysis of Highly Metastatic Circulating Tumor Cells by Combining a Self-Folding Induced Release Reaction with a Cell Capture Microchip.

Nondestructive analysis of the single-cell molecular phenotype of circulating tumor cells (CTCs) is of great significance to the precise diagnosis and treatment of cancer but is also a huge challenge. To address this issue, here, we develop a facile analysis system that integrates CTCs' capture and molecular phenotype analysis. An isothermal nucleic acid amplification technique named self-folding induced release reaction (sFiR), which has high-efficiency signal amplification capabilities and can run under physiological conditions, is first developed to meet the high requirements for sensitivity and nondestructivity. By combining the sFiR with immune recognition and a single cell capture microchip, the molecular phenotype analysis of a single CTC is realized. As a model, nondestructive analysis of junction plakoglobin (JUP), an overexpressed membrane protein that is closely related to the metastasis of CTCs, is successfully achieved. Results reveal that this sFiR-based analysis system can clearly distinguish the expression of JUP in different cancer cell lines and can present quantitative information on the expression of JUP. Furthermore, the captured and analyzed CTCs maintain their basic physiological activity and can be used for drug sensitivity testing. Considering the excellent performance and ease of operation of the system, it can provide technical support for CTC-based cancer liquid biopsy and drug development.

Topological rainbow based on graded topological photonic crystals.

Topological photonic crystal provides a robust platform for nanophotonic devices. However, few reports have been found to realize multiple frequency routing based on topological photonic states, which have restricted further applications in the field of nanophotonic devices. Here, for the first time, to the best of our knowledge, we propose an efficient method to realize a topological rainbow based on graded dielectric topological photonic crystals, which are constructed by changing the degree of lattice contraction and expansion. The topological edge states of different frequencies are separated and trapped at different positions. The all-dielectric planar nanostructures of graded topological photonic crystals are low-loss, robust, and easy for integration. This Letter plays a key role in the use of robust nanophotonic wavelength routers, optical storage, and optical buffers.

Topological Rainbow Concentrator Based on Synthetic Dimension.

Synthetic dimension provides a new platform for realizing topological photonic devices. Here, we propose a method to realize a rainbow concentrator of topological photonic states based on the synthetic dimension concept. The synthetic dimension is constructed using a translational degree of freedom of the nanostructures inside the unit cell of a two-dimensional photonic crystal. The translational deformation induces a nontrivial topology in the synthetic dimension, which gives rise to robust interface states at different frequencies. The topological rainbow can trap states with different frequencies, controlled by tuning the spatial modulation of interface state group velocities. The operation frequency as well as the bandwidth of the topological rainbow can be easily tuned by controlling the band gap of the photonic crystal. The topological principle can be applied to photonic crystals of any symmetry and arbitrary material composition, as long as a complete band gap exists. This Letter provides a new and general scheme for the realization of a topological rainbow concentrator and will be useful for the development of topological photonic devices.

Hybrid photonic-plasmonic nano-cavity with ultra-high Q/V.

Optical cavities with high figure of merit Q/V is essential to enhance the interaction of light and matter. Here, a hybrid photonic-plasmonic nano-cavity, consisting of an L3 photonic crystal nano-cavity and plasmonic bowtie nano-antennas, is proposed to have an ultrahigh figure of merit Q/V of 8.4×106(λ/n)-3, which is the highest value ever demonstrated for all previous works about L3-type photonic crystal nano-cavities. The value of Q/V is enhanced by more than 25 times compared to that in a bare L3 photonic crystal nano-cavity and is 60 times greater than plasmonic bowtie nano-antennas. As a result, the single-atom cooperativity parameter is improved by 26 times with respect to a bare L3 photonic crystal nano-cavity, and strong coupling between light and a single emitter is achieved. The proposed structure provides a new platform to achieve strong coupling between light and a single emitter, which holds great potential for applications in quantum optics, quantum information, and nonlinear optics.

Topological Phase Transition in the Non-Hermitian Coupled Resonator Array.

In a two-dimensional non-Hermitian topological photonic system, the physics of topological states is complicated, which brings great challenges for clarifying the topological phase transitions and achieving precise active control. Here, we prove the topological phase transition exists in a two-dimensional parity-time-symmetric coupled-resonator optical waveguide system. We reveal the inherent condition of the appearance of topological phase transition, which is described by the analytical algebraic relation of coupling strength and the quantity of gain-loss. In this framework, the system can be switched between the topological and trivial states by pumping the site rings. This work provides a new degree of freedom to control topological states and offers a scheme for studying non-Hermitian topological photonics.

Collision-Induced Broadband Optical Nonreciprocity.

Optical nonreciprocity is an essential property for a wide range of applications, such as building nonreciprocal optical devices that include isolators and circulators. The realization of optical nonreciprocity relies on breaking the symmetry associated with Lorentz reciprocity, which typically requires stringent conditions such as introducing a strong magnetic field or a high-finesse cavity with nonreciprocal coupling geometry. Here we discover that the collision effect of thermal atoms, which is undesirable for most studies, can induce broadband optical nonreciprocity. By exploiting the thermal atomic collision, we experimentally observe magnet-free and cavity-free optical nonreciprocity, which possesses a high isolation ratio, ultrabroad bandwidth, and low insertion loss simultaneously. The maximum isolation ratio is close to 40 dB, while the insertion loss is less than 1 dB. The bandwidth for an isolation ratio exceeding 20 dB is over 1.2 GHz, which is 2 orders of magnitude broader than typical resonance-enhanced optical isolators. Our work paves the way for the realization of high-performance optical nonreciprocal devices and provides opportunities for applications in integrated optics and quantum networks.

Vector Exceptional Points with Strong Superchiral Fields.

Exceptional points (EPs), branch points of complex energy surfaces at which eigenvalues and eigenvectors coalesce, are ubiquitous in non-Hermitian systems. Many novel properties and applications have been proposed around the EPs. One of the important applications is to enhance the detection sensitivity. However, due to the lack of single-handed superchiral fields, all of the proposed EP-based sensing mechanisms are only useful for the nonchiral discrimination. Here, we propose theoretically and demonstrate experimentally a new type of EP, which is called a radiation vector EP, to fulfill the homogeneous superchiral fields for chiral sensing. This type of EP is realized by suitably tuning the coupling strength and radiation losses for a pair of orthogonal polarization modes in the photonic crystal slab. Based on the unique modal-coupling property at the vector EP, we demonstrate that the uniform superchiral fields can be generated with two beams of lights illuminating the photonic crystal slab from opposite directions. Thus, the designed photonic crystal slab, which supports the vector EP, can be used to perform surface-enhanced chiral detection. Our findings provide a new strategy for ultrasensitive characterization and quantification of molecular chirality, a key aspect for various bioscience and biomedicine applications.

The first case of teeth discoloration induced by linezolid in children in China Mainland.

Linezolid is an oxazolidinone antimicrobial agent often used to treat multidrug-resistant Gram-positive bacterial infections. The common adverse reactions of linezolid are diarrhea, nausea, headache and bone marrow suppression, and so on. Here, we report the first case of teeth discoloration induced by linezolid linked with extrinsic discoloration in China Mainland. This case report highlights a rare adverse reactions of a commonly used antibiotic.

Ultrasmall broadband wavelength and polarization router based on hybrid waveguide of monolithic-LiNbO3.

The nanoscale wavelength and polarization router, which can simultaneously separate wavelength and polarization modes, is an essential component of on-chip nanophotonic devices. Here, an on-chip wavelength and polarization router is realized experimentally based on a three-layer hybrid waveguide of Au-SiO2-LiNbO3 etched with asymmetric nano-cavities. The central area size of the device is only 1.60×1.96 µm2. A broad operation band covers from 500 nm to 1150 nm with low cross talk of under 10 dB. The monolithic-LiNbO3is introduced for the first time, to the best of our knowledge, to on-chip multichannel wavelength and polarization routers. This work plays a key role for dense chip integration, visible light displays, and communications, and can inspire LiNbO3-based nanophotonic devices.

Spin-controlled topological phase transition in non-Euclidean space.

Modulation of topological phase transition has been pursued by researchers in both condensed matter and optics research fields, and has been realized in Euclidean systems, such as topological photonic crystals, topological metamaterials, and coupled resonator arrays. However, the spin-controlled topological phase transition in non-Euclidean space has not yet been explored. Here, we propose a non-Euclidean configuration based on Möbius rings, and we demonstrate the spin-controlled transition between the topological edge state and the bulk state. The Möbius ring, which is designed to have an 8π period, has a square cross section at the twist beginning and the length/width evolves adiabatically along the loop, accompanied by conversion from transverse electric to transverse magnetic modes resulting from the spin-locked effect. The 8π period Möbius rings are used to construct Su-Schrieffer-Heeger configuration, and the configuration can support the topological edge states excited by circularly polarized light, and meanwhile a transition from the topological edge state to the bulk state can be realized by controlling circular polarization. In addition, the spin-controlled topological phase transition in non-Euclidean space is feasible for both Hermitian and non-Hermitian cases in 2D systems. This work provides a new degree of polarization to control topological photonic states based on the spin of Möbius rings and opens a way to tune the topological phase in non-Euclidean space.

Ceftazidime-avibactam induced renal disorders: past and present.

With the increasing prevalence of multidrug-resistant Gram-negative bacterial pathogens worldwide, antimicrobial resistance has become a significant public health concern. Ceftazidime-avibactam (CAZ-AVI) exhibited excellent in vitro activity against many carbapenemase-producing pathogens, and was widely used for the treatment of various complicated infections. CAZ-AVI is well tolerated across all dosing regimens, and its associated acute kidney injury (AKI) in phase II/III clinical trials is rare. However, recent real-world studies have demonstrated that CAZ-AVI associated AKI was more frequent in real-world than in phase II and III clinical trials, particularly in patients receiving concomitant nephrotoxic agents, with critically ill patients being at a higher risk. Herein, we reviewed the safety data related to renal impairment of CAZ-AVI, and discussed its pharmacokinetic/pharmacodynamic targets and dosage adjustment in patients with impaired renal function. This review aimed to emphasize the importance for healthcare professionals to be aware of this adverse event of CAZ-AVI and provide practical insights into the dosage optimization in critically ill patients with renal dysfunction.

Information-entropy enabled identifying topological photonic phase in real space.

The topological photonics plays an important role in the fields of fundamental physics and photonic devices. The traditional method of designing topological system is based on the momentum space, which is not a direct and convenient way to grasp the topological properties, especially for the perturbative structures or coupled systems. Here, we propose an interdisciplinary approach to study the topological systems in real space through combining the information entropy and topological photonics. As a proof of concept, the Kagome model has been analyzed with information entropy. We reveal that the bandgap closing does not correspond to the topological edge state disappearing. This method can be used to identify the topological phase conveniently and directly, even the systems with perturbations or couplings. As a promotional validation, Su-Schrieffer-Heeger model and the valley-Hall photonic crystal have also been studied based on the information entropy method. This work provides a method to study topological photonic phase based on information theory, and brings inspiration to analyze the physical properties by taking advantage of interdisciplinarity.

Ultracompact and multifunctional integrated photonic platform.

Realizing a multifunctional integrated photonic platform is one of the goals for future optical information processing, which usually requires large size to realize due to multiple integration challenges. Here, we realize a multifunctional integrated photonic platform with ultracompact footprint based on inverse design. The photonic platform is compact with 86 inverse designed-fixed couplers and 91 phase shifters. The footprint of each coupler is 4 µm by 2 µm, while the whole photonic platform is 3 mm by 0.2 mm-one order of magnitude smaller than previous designs. One-dimensional Floquet Su-Schrieffer-Heeger model and Aubry-André-Harper model are performed with measured fidelities of 97.90 (±0.52) % and 99.34 (±0.44) %, respectively. We also demonstrate a handwritten digits classification task with the test accuracy of 87% using on-chip training. Moreover, the scalability of this platform has been proved by demonstrating more complex computing tasks. This work provides an effective method to realize an ultrasmall integrated photonic platform.

All-optical logic gates based on nanoscale plasmonic slot waveguides.

We report realizations of nanoscale integrated all-optical XNOR, XOR, NOT, and OR logic gates using plasmonic slot waveguides based on linear interference between surface plasmon polariton modes. The miniature device size with lateral dimensions smaller than 5 µm, precisely controlled optical phase difference, and quasi-monochromatic surface plasmon polariton modes excited by a continuous wave 830 nm laser beam ensure a high intensity contrast ratio of 24 dB between the output logic states "1" and "0". Compared with previous reported results, the intensity contrast ratio is enhanced 4-fold, whereas the lateral dimension is reduced 4-fold. These compact logic devices are stable, robust, free from environmental impact, and much suitable for practical on-chip applications. These also provide a means to construct all-optical logic devices and nanophotonic processors.