Singular optical propagation properties of two types of one-dimensional anti-PT-symmetric periodic ring optical waveguide networks

Two types of one-dimensional(1D)anti-PT-symmetric periodic ring optical waveguide networks,consisting of gain and loss materials,are constructed.The singular optical propagation properties of these networks are investigated.The results show that the system composed of gain materials exhibits characteristics of ultra-strong transmission and bidirectional reflection.Conversely,the system composed of loss materials demonstrates equal transmittance and reflectance at some frequencies.In both the systems,a new type of total reflection phenomenon is observed.When the imaginary part of the refractive indices of waveguide segments is smaller than 10-5,the system shows bidirectional transparency with the transmittance tending to be 1 and reflectivity to be smaller than 10-8 at some bands.When the refractive indices of the waveguide segments are real,the system will be bidirectional transparent at the full band.These findings may deepen the understanding of anti-PT-symmetric optical systems and optical waveguide networks,and possess potential applications in efficient optical energy storage,ultra-sensitive optical filters,ultra-sensitive all-optical switches,integrated optical chips,stealth physics,and so on.

Monascus pigment-protected bone marrow-derived stem cells for heart failure treatment

Mesenchymal stem cells(MSCs)have demonstrated significant therapeutic potential in heart failure(HF)treatment.However,their clinical application is impeded by low retention rate and low cellular activity of MSCs caused by high inflammatory and reactive oxygen species(ROS)microenvironment.In this study,monascus pigment(MP)nanoparticle(PPM)was proposed for improving adverse microenvironment and assisting in transplantation of bone marrow-derived MSCs(BMSCs).Meanwhile,in order to load PPM and reduce the mechanical damage of BMSCs,injectable hydrogels based on Schiff base cross-linking were prepared.The PPM displays ROS-scavenging and macrophage phenotype-regulating capabilities,significantly enhancing BMSCs survival and activity in HF microenvironment.This hydrogel demonstrates superior biocompatibility,injectability,and tissue adhesion.With the synergistic effects of injectable,adhesive hydrogel and the microenvironment-modulating properties of MP,cardiac function was effectively improved in the pericardial sac of rats.Our results offer insights into advancing BMSCs-based HF therapies and their clinical applications.

Extraordinary characteristics for one-dimensional parity-time-symmetric periodic ring optical waveguide networks

In this paper, we design a one-dimensional （1D） parity-time-symmetric periodic ring optical waveguide network （PTSPROWN） and investigate its extraordinary optical characteristics. It is found that quite different from traditional vacuum/dielectric optical waveguide networks, 1D PTSPROWN cannot produce a photouic ordinary propagation mode, but can generate simultaneously two kinds of photonic nonpropagation modes： attenuation propagation mode and gain propagation mode. It creates neither passband nor stopband and possesses no photonic band structure. This makes 1D PTSPROWN possess richer spontaneous PT-symmetric breaking points and causes interesting extremum spontaneous PT-symmetric breaking points to appear, where electromagnetic waves can create ultrastrong extraordinary transmission, reflection, and localization, and the maximum can arrive at 6.6556 × 10^12 and is more than 7 orders of magnitude larger than the results reported previously. 1D PTSPROWN may possess potential in designing high-efficiency optical energy saver devices, optical amplifiers, optical switches with ultrahigh monochromaticity, and so on.

Four-channel metasurface for multiplexing images under two nonorthogonal polarization states

By its unparalleled capacity to manipulate optical parameters,metasurfaces demonstrate the ability to simultaneously manipulate the amplitude and phase of incident light.Exhibiting both near-field nanoprinting images and far-field holography images is a quintessential illustration of this capability.In preceding investigations,image multiplexing commonly transpires within the single polarization state or orthogonal polarization states,thereby exhibiting a deficiency in terms of information security when contrasted with the nonorthogonal polarization states.In this research,a multifunctional metasurface with the capability of exhibiting four-channel images has been proposed by using a nanobrick as a quarter-wave plate.Through the adjustment of the orientation angles of each nanobrick,nanoprinting can be displayed under both linearly and circularly polarized light.Building on this,the propagation phase is combined with the geometric phase to generate diverse phase delays,enabling the metasurface to be multiplexed under two nonorthogonal polarization states to achieve four-channel image displays.Intriguingly,bidirectional nanoprinting and bidirectional holography can be achieved by altering the direction of incidence polarization states.The proposed metasurface platform can open new possibilities for creating compact multifunctional optical devices,while also enhancing applications in multichannel image displays,information anticounterfeiting,and encryption.