[en] We have theoretically studied the absorption performances of microwave absorbers made of ferromagnetic films. For films with different frequency dispersive types of permeability, we have found that only the films with relaxation type of permeability can be used to realize broadband microwave absorbers with thin thickness. The condition for optimal absorption has also been derived. As the demonstrations, we have designed the magnetic film absorbers using Ni–Zn–Co ferrite film and iron nanofilm, respectively. Deploying periodic multilayer structure, the absorbers work at the optimal absorption condition. The numerical results show our absorbers have good absorption performances in broadband microwave frequency range. - Highlights: • The ultrathin broadband absorber using relaxation type of magnetic film is discussed. • The optimal absorption condition for magnetic film absorber is derived. • A periodic multilayer structure is used to meet the optimal absorption condition. • The absorbers are demonstrated using the Ni–Zn–Co ferrite film and iron nanofilm

[en] Transmission characteristics of two-dimensional magnetized magnetic photonic crystals (MPCs) have been studied by electromagnetic simulation and experiments in microwave frequencies. MPCs with square and hexagonal lattices are made of ferrites, and their transmission coefficients are measured in the X waveband with an applied static magnetic field. For the lattices, a stop-band and a band shift with the applied static magnetic field are observed. The experimental results are in good agreement with those of electromagnetic simulations when magnetic anisotropy of ferrites is represented by a tensor but deviate from the simulation results when the anisotropy is modelled by an effective permeability of TM_z mode

[en] Two-dimensional topological photonic crystals have rapidly emerged as a recent and fascinating branch of photonic research. However, most of them were limited to a specific type of polarization, TE or TM polarization. Here, we explored the dual-polarization topological phases in two-dimensional magnetic photonic crystal (PC) which are composed of ferrite rod clusters in the plasma background. Under the perturbations of the bias magnetic field and/or the cluster distortion in the unit cell, the PC exhibited dual-polarization topological phases, including the quantum Hall (QH) phase, the higher-order quantum spin Hall (HO-QSH) phase and the conventional insulator (CI) phase. We studied the topological nature of these phases by the Wilson loop, Chern number, and unidirectional edge states. Intriguingly, we showed that the HO-QSH phases could present in PC of C _3v symmetry instead of being restricted to C _6v symmetry. The lower symmetry enlarges the gap in the edge states, which helps for the emergence of corner states. By continuously deforming the unit cell configuration, we demonstrated the phase transition in the system was dual-polarization. Our results extend the topological phases in the PCs and pave the way for the dual-polarization topological devices and their applications. (paper)

[en] Though topologically protected one-way edge states are determined by the bulk mode of the magnetic photonic crystal (MPC), the edge profile can influence topological edge states and associated wave propagation since the waves at the states are localized at the edge of the photonic crystal. By truncating the honeycomb structured MPC at the same side but at different cuts, we show the MPC slab will present different topological edge band, and the associate transmission of a one-way surface wave will change a lot. We demonstrate the good transmission efficiency of the one-way surface wave needs a good field localization at the edge of MPC at the topological edge states, and bearded edge has better field localization ability than the zigzag one in a wider frequency range. In addition to the different cuts, one can modify the topological edge state by tuning the radius of outmost rods of the slab or the material parameters of the rods, which does not affect the topological state of the MPC. Our study provides an effective means to improve the performances of the devices based on topological edge states of the materials, such as one-way waveguide. (paper)

[en] We theoretically demonstrate that electromagnetic waves can self-collimate and propagate unidirectionally in photonic crystals fabricated using semicylindrical ferrite rods in magnetized states. The parity and time-reversal symmetries of such photonic crystals are broken, resulting in a self-collimated one-way body wave within the photonic crystals. By applying the bias magnetic field in a complex configuration, the self-collimated one-way wave beam can be bent into arbitrary trajectories within the photonic crystal, providing an avenue for controlling wave beams

[en] There exist two types of electromagnetic (EM) one-way edge states in magnetic photonic crystal (MPC). One is associated with photonic band gap (PBG) relevant to Bragg scattering, while the other is associated with PBG originating from magnetic surface plasmon resonance. Both support robust unidirectional wave transmission, but each with relatively limited operating bandwidth. By optimizing the lattice spacing and filling ratio of MPC as well as tuning the external static biasing magnetic field, we are able to fuse the two types of EM one-way edge states together and therefore achieve broadband one-way transmission. The operating bandwidth could be about 4 GHz in a microwave regime; this is much larger than that based on either type, providing a way towards the practical applications of unidirectional wave propagation. (paper)

[en] Highlights: • Formulation of bone extracellular matrix affects its immunomodulatory properties. • Bone extracellular matrix particles elicit pro-inflammatory macrophage responses. • Bone extracellular matrix gels induce macrophages toward pro-healing phenotypes. • Changing ECM particles into gels leads to an enhanced tissue regeneration. -- Abstract: Extracellular matrices (ECMs) derived from native tissues/organs have been used as biomaterials for tissue engineering and regenerative medicine in a wide range of preclinical and clinical settings. The success or failure of these applications is largely contingent on the host responses to the matrices in vivo. Despite retaining their native structural and functional proteins, bone ECM-based transplants have been reported to evoke adverse immune responses in many cases; thus, optimizing the immunomodulatory properties of bone ECMs is critical for ensuring downstream regenerative outcomes. Using a simple digestion-neutralization protocol, we transformed the commonly used bone-derived filler particles into gel bioscaffolds. Instead of inducing macrophages toward proinflammatory (M1) polarization, as reported in the literature and confirmed in the present study for ECM particles, the ECM gels were found to be more likely to polarize macrophages toward regulatory/anti-inflammatory (M2) phenotypes, leading to enhanced tissue regeneration in a rat periodontal defect model. The present work demonstrates a simple, practical and economical strategy to modify the immunomodulatory properties of bone ECMs before their in vivo transplantation and hence has important implications that may facilitate the use of ECM-based bioscaffolds derived from diverse sources of tissues for regenerative purposes.