One-way valley-locked waveguide with a large channel achieved by all-dielectric photonic crystals.

One-way transmission of light constitutes the cornerstone of modern photonic circuits. In the realm of photonic devices, it has been widely utilized in isolators, circulators, etc. Recent topology in artificial materials, an unprecedented degree of freedom, has been proposed to solve the effect of impurities on one-way transmission.

Phase manipulation in reflective phase gradient photonic crystals.

Phase gradient photonic crystals (PGPCs) are proposed as promising candidates for phase manipulation and can enable arbitrary electromagnetic functions, such as deflection and focusing. In stark contrast to the proposed metasurfaces, the phase variation in PGPCs arises from simple edge-configuration rather than structure resonance. Moreover, the reflection magnitude maintains a constant of 1 for the reflective case in the Bragg gap, which affords significant convenience in design.

The standardised Malay version of purdue pegboard test: Content validity and test-retest reliability testing.

Introduction: Purdue Pegboard Test (PPT) is a valid and reliable instrument for measuring hand dexterity among individuals with or without medical conditions. In the Southeast Asia region where Malay is widely spoken, there is a need to have a Malay translation of Purdue Pegboard Test. This study aimed to translate the PPT into the Malay version (PPT-M) and to determine the content validity and test-retest reliability of this translated version.

Hybrid topological photonic crystals.

Topologically protected photonic edge states offer unprecedented robust propagation of photons that are promising for waveguiding, lasing, and quantum information processing. Here, we report on the discovery of a class of hybrid topological photonic crystals that host simultaneously quantum anomalous Hall and valley Hall phases in different photonic band gaps. The underlying hybrid topology manifests itself in the edge channels as the coexistence of the dual-band chiral edge states and unbalanced valley Hall edge states.

Topological edge and corner states in honeycomb-kagome photonic crystals.

We systematically study the first- and second-order band topologies, which are tied to the pseudospin and valley degree of freedoms (DOFs), in honeycomb-kagome photonic crystals (HKPCs). We first demonstrate the quantum spin Hall phase as the first-order pseudospin-induced topology in HKPCs by observing the partial pseudospin-momentum locked edge states. By employing the topological crystalline index, we also discover the multiple corner states emerging in the hexagon-shaped supercell as the manifestation of the second-order pseudospin-induced topology in HKPCs.

Broadband radar cross section reduction by an absorptive metasurface based on a magnetic absorbing material.

A highly feasible approach to achieve a broadband radar cross section (RCS) reduction using a simple magnetic metasurface is presented. A magnetic absorbing material (MAM) with high permittivity and magnetic loss is introduced into the metasurface design instead of the more common dielectric material to considerably reduce its thickness. The metasurface is composed of an optimized two-dimensional array of MAM meta-atoms and a metal plate in back.

An autonomously ultrafast self-healing, highly colourless, tear-resistant and compliant elastomer tailored for transparent electromagnetic interference shielding films integrated in flexible and optical electronics.

Considering the operation reliability of flexible and optical electronics (FOEs) in dynamic and real-world environments, autonomous self-healing electromagnetic interference (EMI) shielding materials with high transparency, good stretchability and excellent tear-resistance are urgently required but always difficult to achieve due to the poor dynamics of their elastic substrates. Herein, we propose a facile strategy to design a highly dynamic polyurea elastomer (PDMS-MPI-HDI) featuring with ultrahigh optical transparency (>94%), ultralow elastic modulus (<1 MPa), high tear-resistant stretchability (800%), and ultrafast autonomous self-healing (100 s for scratch-healing). Taking PDMS-MPI-HDI as a substrate for embedding silver nanowires (Ag NWs), the first transparent, stretchable and self-healable EMI shielding materials (Ag NWs/PDMS-MPI-HDI) are presented.

Bulk-disclination correspondence in topological crystalline insulators.

Most natural and artificial materials have crystalline structures from which abundant topological phases emerge. However, the bulk-edge correspondence-which has been widely used in experiments to determine the band topology from edge properties-is inadequate in discerning various topological crystalline phases, leading to challenges in the experimental classification of the large family of topological crystalline materials. It has been theoretically predicted that disclinations-ubiquitous crystallographic defects-can provide an effective probe of crystalline topology beyond edges, but this has not yet been confirmed in experiments.

Broadband backscattering reduction realized by array of lossy scatterers.

We propose an array of randomly distributed lossy scatterers to achieve broadband backscattering reduction. The array efficiently combines absorption and diffusion functionalities by using three subarrays made of ferromagnetic or dielectric scatterers based on resistive octagonal rings. The subarrays have strong absorption in different frequency bands, whereas they have different reflection phases in a wide frequency band, resulting in -10 dB backscattering reduction in a wide frequency range (from 3.

Transmission and radar cross-section reduction by combining binary coding metasurface and frequency selective surface.

A modified reflective metasurface, which is constructed by replacing the metal ground of the reflective coding metasurface with a bandpass frequency-selective surface, is proposed. The metasurface has transmission and reduction of radar cross-section characteristics. This allows the metasurface to overcome the drawbacks of conventional realizations, which use lossy materials.

Topological light-trapping on a dislocation.

Topological insulators have unconventional gapless edge states where disorder-induced back-scattering is suppressed. In photonics, such edge states lead to unidirectional waveguides which are useful for integrated photonic circuitry. Cavity modes, another type of fundamental component in photonic chips, however, are not protected by band topology because of their lower dimensions.

Manipulating electromagnetic wave propagating non-reciprocally by a chain of ferrite rods.

We demonstrated that non-reciprocal wave propagation could be manipulated by a magnetic rod chain under bias DC magnetic fields. Made of ferrite material YIG and designed working in the microwave X-band, the rod chain exhibited almost a total reflection when the incident wave obliquely impinged on the rod chain, but exhibited nearly a total transmission when the wave reversed its propagation direction. The non-reciprocal wave propagation was due to the non-reciprocal diffraction of the rod chain for the orders 0 and ± 1.

Manipulating one-way space wave and its refraction by time-reversal and parity symmetry breaking.

One-way transmission and negative refraction are the exotic wave properties founded in photonic crystals which attract a great attention due to their promising applications in photonic devices. How to integrate such two phenomena in one material or device is interesting and valuable. In this work, we theoretically and experimentally demonstrate that one-way electromagnetic space wave can be realized by means of two-dimensional magnetic photonic crystals.

Observation of broadband unidirectional transmission by fusing the one-way edge states of gyromagnetic photonic crystals.

We experimentally demonstrate a broadband one-way transmission by merging the operating bands of two types of one-way edge modes that are associated with Bragg scattering and magnetic surface plasmon (MSP) resonance, respectively. By tuning the configuration of gyromagnetic photonic crystals and applied bias magnetic field, the fused bandwidth of unidirectional propagation is up to 2 GHz in microwave frequency range, much larger than either of the individual one-way bandwidth associated with Bragg scattering or MSP resonance. Our scheme for broadband one-way transmission paves the way for the practical applications of one-way transmission.

Realization of self-guided unidirectional waveguides by a chain of gyromagnetic rods.

To achieve a unidirectional transmission waveguide with miniature dimensions and flexible geometry, we propose a self-guided unidirectional waveguide composed of a chain of gyromagnetic rods. Two configurations of the waveguides were demonstrated. One is of a zigzag chain form, the other is a straight-line chain.

Field enhancement of nonreciprocal electromagnetic wave supported by magnetic surface plasmon.

At the zigzag edge of a magnetic photonic crystal with honeycomb lattice, the nonreciprocal surface modes (NSMs) could appear below the magnetic surface plasmon (MSP) frequency. The NSMs possess very flat slopes outside the light line, which is strikingly different from the nearly linear dispersion curve just above the MSP frequency and results in strong confinement and enhancement of the electromagnetic field. Particularly, an enhancement over 100 times in magnetic field is achieved because of the strong magnetic response arising from the MSP resonance.

Investigation of the EDFA effect on the BER performance in space uplink optical communication under the atmospheric turbulence.

In a ground-to-satellite communication system with a preset EDFA, the EDFA's performance will be affected by space environment. With 250 Gy radiation, the EDFA's gain decreases by 2 dB from 19.97 dB at 20 °C.

A circuit model for the hybrid resonance modes of paired SRR metamaterials.

To better understand the resonance modes caused by the interelement couplings in the building block of metamaterials, we propose a circuit model for the hybrid resonance modes of paired split ring resonators. The model identifies the electromagnetic coupling between the paired rings by electric and magnetic coupling networks and well explains the variation of hybrid resonance modes with respect to the distance and the twist angle between the rings. The predictions of our model are further proved by experiments.

Experimental realization of self-guiding unidirectional electromagnetic edge states.

We present an experimental demonstration of self-guiding electromagnetic edge states existing along the zigzag edge of a honeycomb magnetic photonic crystal. These edge states are shown to possess unidirectional propagation characteristics that are robust against various types of defects and obstacles. In particular, they allow for the unidirectional transport of electromagnetic energy without requiring an ancillary cladding layer.

Measurement of ac conductivity of gold nanofilms at microwave frequencies.

We proposed an application of the open-terminal method to measure the alternating current (ac) conductivity of metallic nanometer thick films at microwave frequencies. An explicit expression of the conductivity as a function of reflection has been derived. Using the application, we experimentally measured the complex conductivity of gold nanometer films in microwave X band.