A Predictive 6G Network with Environment Sensing Enhancement:From Radio Wave Propagation Perspective

In order to support the future digital society,sixth generation(6G)network faces the challenge to work efficiently and flexibly in a wider range of scenarios.The traditional way of system design is to sequentially get the electromagnetic wave propagation model of typical scenarios firstly and then do the network design by simulation offline,which obviously leads to a 6G network lacking of adaptation to dynamic environments.Recently,with the aid of sensing enhancement,more environment information can be obtained.Based on this,from radio wave propagation perspective,we propose a predictive 6G network with environment sensing enhancement,the electromagnetic wave propagation characteristics prediction enabled network(EWave Net),to further release the potential of 6G.To this end,a prediction plane is created to sense,predict and utilize the physical environment information in EWave Net to realize the electromagnetic wave propagation characteristics prediction timely.A two-level closed feedback workflow is also designed to enhance the sensing and prediction ability for EWave Net.Several promising application cases of EWave Net are analyzed and the open issues to achieve this goal are addressed finally.

Terahertz polarization sensing,chirality enhancement,and specific binding based on metasurface sensors for biochemical detection:a review[Invited]

Specific and highly-sensitive biochemical detection technology is particularly important in global epidemics and has critical applications in life science,medical diagnosis,and pharmaceutics.As a newly developed technology,the THz metamaterialbased sensing method is a promising technique for extremely sensitive biomolecular detection.However,due to the significant resonant peaks generated by THz metamaterials,the characteristic absorption peaks of the analyte are usually masked,making it difficult to distinguish enantiomers and specifically identify target biomolecules.Recently,new ways to overcome this limitation have become possible thanks to the emergence of chiral metasurfaces and the polarization sensing method.Additionally,functionalized metasurfaces modified by antibodies or other nanomaterials are also expected to achieve specific sensing with high sensitivity.In this review,we summarize the main advances in THz metamaterials-based sensing from a historical perspective as well as application in chiral recognition and specific detection.Specifically,we introduce the basic theory and key technology of THz polarization spectrum and chiral sensing for biochemical detection,and immune sensing based on biomolecular interaction is also discussed.We mainly focus on chiral recognition and specific sensing using THz metasurface sensors to cover the most recent advances in the topic,which is expected to break through the limitations of traditional THz absorption spectroscopy and chiral spectroscopy in the visible-infrared band and develop into an irreplaceable method for the characterization of biochemical substances.

Enhancing sensing capacity of terahertz metamaterial absorbers with a surface-relief design

Metamaterial absorbers(MAs)serve as important electromagnetic wave-absorbing devices that have captured the attention of researchers for a long term.Functioning as sensitive detectors to determine perturbations in an ambient environment is another significant subsidiary function.Here,we theoretically propose an optimized fabrication method to implement terahertz MAs with fewer steps and also evaluate both absorption and sensing performances of such MAs realized by the new method.Simulation findings demonstrate that such MAs can basically maintain the original absorption features perfectly,including near-complete absorption at resonance as well as strong robustness to wide incident angles.Specifically,the full width at half-maximum and quality factor of the absorption resonances attenuate less than 26%and 8%with this new method,remaining in the ranges of^0.03–0.04 THz and^20–27 for two selected example MAs.More significantly,sensing capacities of this type of MA,in terms of maximum detection range(enhancing at least 9%),observable spectral modulation(increasing at least 6.3%),and refractive index sensitivity,are improved to a large extent because of more intense coupling between resonant field and matter in the case of surface-relief MAs.This stronger coupling results from exposing more spots of the resonantly high field to direct contact with an approaching analyte,which is illustrated by field profiles of the MAs at resonance in this work.Additionally,other desirable absorber features are also explored with such MAs,like functioning as building blocks to configure multiband MAs and strong robustness against fabrication errors.Such new-style terahertz MAs shown in the paper,acting as good examples,not only prove that terahertz MAs can be fabricated by the proposed time-and cost-saving route in contrast to the traditional MA fabrication process,but also can serve as novel platforms to explore other intriguing terahertz photonic effects,such as the field enhancement effect.

Metamaterials beyond negative refractive index： Applications in telecommunication and sensing

Metamaterials have earned their name with extraordinary properties such as negative refractive index and invisibility cloaking. With over 15 years of research and development, metamaterials show their debut in real world applications, especially in the areas of telecommunication, sensing, aerospace & defense, optics and medical instrumentation. In the meanwhile, metamaterials are expanding their concept in areas beyond electromagnetics. In this paper, the authors would like to focus on the research and applications in telecommunication and sensing. Octave-bandwidth horn antennas, flat-panel satellite antennas and air-borne holographic satellite antennas are all fabulous examples of clever implementation that bring metamaterials into practical devices. We would like to discuss the features that differentiate metamaterials from conventional counterparts in case studies. With the advancement in design, manufacturing, packaging, detection and testing, more sophisticated features are expected in the telecommunication, sensing, and beyond.

A performance enhanced Rayleigh Brillouin optical time domain analysis sensing system

Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio(SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 d B higher than that with single wavelength, the Brillouin frequency shift(BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed technique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.

Light controlled imaging probes for intracellular target recognition： photochromism as a tool to enhance sensing precision

Chemosensors and imaging probes have been the focus of significant research interest over the past few decades. In part due to ease of preparation and simplicity in manipulation, fluorescent probes have been extensively used for biomedical applications. When used for #7 vitro cell imaging [1,2],