We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each squa...We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each square metal patch surrounded by the square loop apertures have been truncated, so it becomes an orthotropic structure with a pair of mutually perpendicular symmetric axes u and v. The simulated results show that the metasurface can be used as a wideband transmission-type polarization converter to realize linear-to-circular polarization conversion in the frequency range from12.21 GHz to 18.39 GHz, which is corresponding to a 40.4% fractional bandwidth. Moreover, its transmission coefficients at x-and y-polarized incidences are completely equal. We have analyzed the cause of the polarization conversion, and derived several formulas which can be used to calculate the magnitudes of cross-and co-polarization transmission coefficients at y-polarized incidence, together with the phase difference between them, based on the two independent transmission coefficients at u-and v-polarized incidences. Finally, one experiment was carried out, and the experiment and simulated results are in good agreement with each other.展开更多
An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on...An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on grounded dielectric substrate and covered with a dielectric layer, which is an orthotropic anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along the directions with the tilt angles of ±45° with respect to the vertical y axis. When the u- and v-polarized waves are incident on the proposed metasurface, the phase difference between the two reflection coefficients is close to –90° in an ultra-wide frequency band, so it can realize high-efficiency and ultra-wideband LTC polarization conversion under both x- and y-polarized incidences in this band. The proposed polarization conversion metasurface is simulated and measured. Both the simulated and measured results show that the axial ratio (AR) of the reflected wave is kept below 3 dB in the ultra-wide frequency band of 5.87 GHz–21.13 GHz, which is corresponding to a relative bandwidth of 113%;moreover, the polarization conversion rate (PCR) can be kept larger than 99% in a frequency range of 8.08 GHz–20.92 GHz.展开更多
In this paper, a linear-to-circular polarization converter using a three-layer frequency selective surface based on Ishaped circular structure resonant is presented and investigated. Numerical simulations exhibit that...In this paper, a linear-to-circular polarization converter using a three-layer frequency selective surface based on Ishaped circular structure resonant is presented and investigated. Numerical simulations exhibit that when the normal ypolarized waves impinge on this device propagating towards ＋z direction, the two orthogonal components of the transmitted waves have a 90° phase difference as well as the nearly equal amplitudes at the resonant frequency of 7.04 GHz, which means that the left-hand circular polarization is realized in transmission. For validating the proposed design, a prototype which consists of 25 × 25 elements has been designed, manufactured and measured. The measured results are in good agreement with the simulated ones, showing that the polarization conversion transmission is over-3 dB in the frequency range of 5.22–8.08 GHz and the axial ratio is below 3 dB from 5.86 GHz to 7.34 GHz.展开更多
Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,how...Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.展开更多
Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)field.Based on the unique energy band ...Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)field.Based on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible solution.Herein,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted strategy.These composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA performance.The results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural distortion.Moreover,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy attenuation.This study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.展开更多
Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors c...Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static stimuli.Here,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic stimuli.Specifically,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential differences.The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized.Then,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs.Compared with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior bio-friendliness.As demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning algorithms.This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.展开更多
The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic...The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic crystals.This offers significant potential in optics and photonics.Here,we reveal that in complex lattices far-field polarization singularities can be flexibly manipulated while preserving structural symmetry.A change in topological charge for the at-ΓBIC can generate new BICs or CPSs.At an off-Γpoint,a BIC can spawn from the collision of two CPSs.As the thickness of the structure increases,this BIC will meet the at-ΓBIC.The merging of BICs can induce topological charge transition and yield a large wavevector space around theΓpoint with ultra-high quality(Q)factors.Our findings provide a novel degree of freedom for manipulating polarization singularities,which holds great promise in radiation modulation and singular optics.展开更多
Correction to:Nano-Micro Lett.(2025)17:24 https://doi.org/10.1007/s40820-024-01515-0 Following publication of the original article[1],the authors reported the author list needed to be updated because the last three au...Correction to:Nano-Micro Lett.(2025)17:24 https://doi.org/10.1007/s40820-024-01515-0 Following publication of the original article[1],the authors reported the author list needed to be updated because the last three author names were duplicated.The correct author list has been provided in this Correction.The original article[1]has been corrected.展开更多
Enhancing the sensitivity of nuclear magnetic resonance(NMR)technology has been the focus of NMR research for decades,which offers the potential to significantly expand its applications in chemistry,biology,and medica...Enhancing the sensitivity of nuclear magnetic resonance(NMR)technology has been the focus of NMR research for decades,which offers the potential to significantly expand its applications in chemistry,biology,and medical imaging.Parahydrogen-induced polarization(PHIP)emerges as a cost-effective approach to substantially enhance the sensitivity of NMR.Nevertheless,the amplification of the ^(1)H signal in PHIP is susceptible to interference from the thermal polarization state ^(1)H NMR signal.Employing RASER(radiofrequency amplification by stimulated emission of radiation)proves effective in mitigating such interference,which can reduce the linewidth and increase the sensitivity at the same time.In this work,we utilized PHIP and RASER to enhance the signal-to-noise ratio(SNR)of a series of biocompatible alkynyl organic acid molecules.The alkynyl acid with the highest enhancement factor was first identified through PASADENA(parahydrogen and synthesis allow dramatically enhanced nuclear alignment)experiments.Subsequently,RASER experiments were carried out through hyperpolarization of 5-hexynoic acid,exploring its signal characteristics under varying flow rates and pressures.The SNR of proton signals of 5-hexynoic acid surpassed 150,000,an 18.62-fold improvement compared with traditional hyperpolarized signals in PASADENA,and a markedly narrowed linewidth of 0.06 Hz.展开更多
Na_(3)V_(2)(PO_(4))_(2)O_(2)F (VP) is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific capacity.Density functional theory (DFT) and finite el...Na_(3)V_(2)(PO_(4))_(2)O_(2)F (VP) is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific capacity.Density functional theory (DFT) and finite element simulations show that incorporating SO_(4)^(2-)into VP decreases its band gap,lowers the migration energy barrier,and ensures a uniform Na+concentration gradient and stress distribution during charge and discharge cycles.Consequently,the average Na+diffusion coefficient of Na_(3)V_(2)(PO_(4))_(1.95)(SO_(4))_(0.05)O_(2)F(VPS-1) is roughly double that of VP,leading to enhanced rate capability (80 C,75.5 mAh g^(-1)) and cycling stability (111.0 mAh g^(-1)capacity after 1000 cycles at 10 C current density) for VPS-1.VPS-1 exhibits outstanding fast-charging capabilities,achieving an 80%state of charge in just 8.1 min.The assembled VPS-1//SbSn/NPC full cell demonstrated stable cycling over 200 cycles at a high 5 C current,maintaining an average coulombic efficiency of 95.35%.展开更多
Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajec...Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.展开更多
A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads t...A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads to a significant optical loss.The theoretical maximum optical efficiency is merely 25%.To transcend this optical efficiency constraint while retaining the foldable characteristic inherent to traditional pancake optics,in this paper,we propose a theoretically lossless folded optical system to replace the HM with a nonreciprocal polarization rotator.In our feasibility demonstration experiment,we used a commercial Faraday rotator(FR)and reflective polarizers to replace the lossy HM.The theoretically predicted 100%efficiency can be achieved approximately by using two high-extinction-ratio reflective polarizers.In addition,we evaluated the ghost images using a micro-OLED panel in our imaging system.Indeed,the ghost images can be suppressed to undetectable level if the optics are with antireflection coating.Our novel pancake optical system holds great potential for revolutionizing next-generation VR displays with lightweight,compact formfactor,and low power consumption.展开更多
Homogeneous heterogeneous(heterophase)interfaces regulated with low energy barriers have a fast response to applied electric fields and could provide a unique interfacial polarization,which facilitate the transport of...Homogeneous heterogeneous(heterophase)interfaces regulated with low energy barriers have a fast response to applied electric fields and could provide a unique interfacial polarization,which facilitate the transport of electrons across the substrate.Such regulation on the interfaces is effective in modulating electromagnetic wave absorbing materials.Herein,we construct NbS_(2)–NiS_(2)heterostructures with NiS_(2)nanoparticles uniformly grown in NbS_(2)hollow nanospheres,and such particular structure enhances the interfacial polarization.The strong electron transfer at the interface promotes electron transport throughout the material,which results in less scattering,promotes conduct ion loss and dielectric polarization relaxation,improves dielectric loss,and results in a good impedance matching of the material.Consequently,the absorbing band may be successful tuned.By regulating the amount of NiS_(2),the heterogeneous interface is finely alternated so that the overall wave-absorbing performance is shifted to lower frequencies.With a NiS_(2)content of 15 wt%and an absorber thickness of 1.84 mm,the minimum reflection loss at 14.56 GHz is53.1 dB,and the effective absorption bandwidth is 5.04 GHz;more importantly,the minimum reflection loss in different bands is20 dB,and the microwave energy absorption rate reaches 99%when the thickness is about 1.5–4.5 mm.This work demonstrates the construction of homogeneous heterostructures is effective in improving the electromagnetic absorption properties,providing guideline for the synthesis of highly efficient electromagnetic absorbing materials.展开更多
Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quas...Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr_(2) by using combined measurements of the angle-resolved polarized Raman spectroscopy(ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr_(2) flake.And anisotropic optical absorption spectrum of PdBr_(2) nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr_(2) nanowire exhibits high responsivity of 747 A·W^(-1) and specific detectivity of 5.8×10^(12) Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr_(2), establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.展开更多
An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdope...An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdoped oscillator and two-stage amplifiers with polarization maintaining commercial silica fibers and devices, which can provide robust and stable soliton generation. High-power soliton laser with the average power of 0.28 W,the repetition rate of 42.7 MHz, and pulse duration of 515 fs is generated directly from the main amplifier.Our experiment provides a feasible method for high-power all-fiber polarization maintaining femtosecond laser generation working at 1.7 μm.展开更多
Orthogonal matrices have become a vital means for coding and signal processing owing to their unique distributional properties.Although orthogonal matrices based on amplitude or phase combinations have been extensivel...Orthogonal matrices have become a vital means for coding and signal processing owing to their unique distributional properties.Although orthogonal matrices based on amplitude or phase combinations have been extensively explored,the orthogonal matrix of polarization combinations(OMPC)is a novel,relatively unexplored concept.Herein,we propose a method for constructing OMPCs of any dimension encompassing 4n(where n is 1,2,4,8,…)mutually orthogonal 2ncomponent polarization combinations.In the field of holography,the integration of polarization multiplexing techniques with polarization-sensitive materials is expected to emerge as a groundbreaking approach for multichannel hologram multiplexing,offering considerable enhancements in data storage capacity and security.A multidimensional OMPC enables the realization of multichannel multiplexing and dynamical modulation of information in polarization holographic recording.Despite consolidating all information into a single position within the material,we effectively avoided extraneous crosstalk during the reconstruction process.Our results show that achieving four distinct holographic images individually and simultaneously depends on the polarization combination represented by the incident wave.This discovery opens up a new avenue for achieving highly holographic information storage and dynamically displayed information,harnessing the potential of OMPC to expand the heretofore limited dimensionality of orthogonal polarization.展开更多
For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relatio...For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relationship between spin polarization of ferromagnet and the insulating barrier thickness in MTJs.Here,we investigate the influence of alumina barrier thickness on tunneling spin polarization(TSP)through a combination of theoretical calculations and experimental verification.Our simulating results reveal a significant impact of barrier thickness on TSP,exhibiting an oscillating decay of TSP with the barrier layer thinning.Experimental verification is realized on FeNi/AlO_(x)/Al superconducting tunnel junctions to directly probe the spin polarization of FeNi ferromagnet using Zeeman-split tunneling spectroscopy technique.These findings provide valuable insights for designs of high-performance spintronic devices,particularly in applications such as magnetic random access memories,where precise control over the insulating barrier layer is crucial.展开更多
Terahertz polarization conversion devices have significant potential applications in various fields such as terahertzimaging and spectroscopy.In this paper,we utilize genetic algorithms to topologically optimize the m...Terahertz polarization conversion devices have significant potential applications in various fields such as terahertzimaging and spectroscopy.In this paper,we utilize genetic algorithms to topologically optimize the metasurface unit cellsand design a reflective linear polarization conversion metasurface with ultra-broadband and wide-angle characteristics.By partitioning the metallic pattern layer into quadrants,the encoding length is effectively reduced,resulting in a shorteroptimization time.The research results indicate that the converter possesses a polarization conversion efficiency ratio higherthan 90%and a relative bandwidth ratio of 125%in a range of 0.231-0.995 THz.Meanwhile,it can maintain excellentpolarization conversion properties when the incident angle of terahertz waves is less than 45°and the polarization angle isless than 15°,demonstrating excellent practicality.New insights are provided for the design of terahertz wide-angle ultrawidebandpolarization conversion devices,and the proposed metasurfce has potential applications in terahertz polarizationimaging,spectroscopy and communication fields.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61471387)the Research Center for Internet of Things and Big Data Technology of Xijing University,China
文摘We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each square metal patch surrounded by the square loop apertures have been truncated, so it becomes an orthotropic structure with a pair of mutually perpendicular symmetric axes u and v. The simulated results show that the metasurface can be used as a wideband transmission-type polarization converter to realize linear-to-circular polarization conversion in the frequency range from12.21 GHz to 18.39 GHz, which is corresponding to a 40.4% fractional bandwidth. Moreover, its transmission coefficients at x-and y-polarized incidences are completely equal. We have analyzed the cause of the polarization conversion, and derived several formulas which can be used to calculate the magnitudes of cross-and co-polarization transmission coefficients at y-polarized incidence, together with the phase difference between them, based on the two independent transmission coefficients at u-and v-polarized incidences. Finally, one experiment was carried out, and the experiment and simulated results are in good agreement with each other.
基金Project supported by the Natural Science Foundation of Shaanxi Province, China (Grant Nos. 2019JM-077 and 2018JM-6098)the Scientific Research Program Funded by Shaanxi Provincial Education Department (Grant No. 18JK1195)the Shaanxi Key Research and Development Project, China (Grant No. 2019GY-055).
文摘An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on grounded dielectric substrate and covered with a dielectric layer, which is an orthotropic anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along the directions with the tilt angles of ±45° with respect to the vertical y axis. When the u- and v-polarized waves are incident on the proposed metasurface, the phase difference between the two reflection coefficients is close to –90° in an ultra-wide frequency band, so it can realize high-efficiency and ultra-wideband LTC polarization conversion under both x- and y-polarized incidences in this band. The proposed polarization conversion metasurface is simulated and measured. Both the simulated and measured results show that the axial ratio (AR) of the reflected wave is kept below 3 dB in the ultra-wide frequency band of 5.87 GHz–21.13 GHz, which is corresponding to a relative bandwidth of 113%;moreover, the polarization conversion rate (PCR) can be kept larger than 99% in a frequency range of 8.08 GHz–20.92 GHz.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61471387,61271250,and 61571460)
文摘In this paper, a linear-to-circular polarization converter using a three-layer frequency selective surface based on Ishaped circular structure resonant is presented and investigated. Numerical simulations exhibit that when the normal ypolarized waves impinge on this device propagating towards ＋z direction, the two orthogonal components of the transmitted waves have a 90° phase difference as well as the nearly equal amplitudes at the resonant frequency of 7.04 GHz, which means that the left-hand circular polarization is realized in transmission. For validating the proposed design, a prototype which consists of 25 × 25 elements has been designed, manufactured and measured. The measured results are in good agreement with the simulated ones, showing that the polarization conversion transmission is over-3 dB in the frequency range of 5.22–8.08 GHz and the axial ratio is below 3 dB from 5.86 GHz to 7.34 GHz.
基金financially supported by the National Natural Science Foundation of China(Grants nos.62201411,62371378,22205168,52302150 and 62304171)the China Postdoctoral Science Foundation(2022M722500)+1 种基金the Fundamental Research Funds for the Central Universities(Grants nos.ZYTS2308 and 20103237929)Startup Foundation of Xidian University(10251220001).
文摘Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies,as well as veiled dielectric-responsive character,are instrumental in electromagnetic dissipation.Conventional methods,however,constrain their delicate constructions.Herein,an innovative alternative is proposed:carrageenan-assistant cations-regulated(CACR)strategy,which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix.This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction,benefiting the delicate construction of defects-rich heterostructures in M_(x)S_(y)/carbon composites(M-CAs).Impressively,these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and,simultaneously,induct local asymmetry of electronic structure to evoke large dipole moment,ultimately leading to polarization coupling,i.e.,defect-type interfacial polarization.Such“Janus effect”(Janus effect means versatility,as in the Greek two-headed Janus)of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time.Consequently,the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm,compared to sulfur vacancies-free CAs without any dielectric response.Harnessing defects-rich heterostructures,this one-pot CACR strategy may steer the design and development of advanced nanomaterials,boosting functionality across diverse application domains beyond electromagnetic response.
基金supported by National Natural Science Foundation of China(NSFC 52432002,52372041,52302087)Heilongjiang Touyan Team Program,the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2021003)the Shanghai Aerospace Science and Technology Innovation Fund(SAST2022-60).
文摘Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)field.Based on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible solution.Herein,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted strategy.These composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA performance.The results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural distortion.Moreover,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy attenuation.This study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.
基金financially supported by the Sichuan Science and Technology Program(2022YFS0025 and 2024YFFK0133)supported by the“Fundamental Research Funds for the Central Universities of China.”。
文摘Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots.Compared to active sensing devices,passive piezoelectric and triboelectric tactile sensors consume less power,but lack the capability to resolve static stimuli.Here,we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired,passive,and bio-friendly tactile sensors for resolving both static and dynamic stimuli.Specifically,to emulate the polarization process of natural sensory cells,conjugated polymers(including poly(3,4-ethylenedioxythiophen e):poly(styrenesulfonate),polyaniline,or polypyrrole)are controllably polarized into two opposite states to create artificial potential differences.The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized.Then,a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs.Compared with the currently existing tactile sensing devices,the developed tactile sensors feature distinct characteristics including fully organic composition,high sensitivity(up to 773 mV N^(−1)),ultralow power consumption(nW),as well as superior bio-friendliness.As demonstrations,both single point tactile perception(surface texture perception and material property perception)and two-dimensional tactile recognitions(shape or profile perception)with high accuracy are successfully realized using self-defined machine learning algorithms.This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.
基金Project supported by the National Natural Science Foundation of China(Grant No.12374205)。
文摘The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic crystals.This offers significant potential in optics and photonics.Here,we reveal that in complex lattices far-field polarization singularities can be flexibly manipulated while preserving structural symmetry.A change in topological charge for the at-ΓBIC can generate new BICs or CPSs.At an off-Γpoint,a BIC can spawn from the collision of two CPSs.As the thickness of the structure increases,this BIC will meet the at-ΓBIC.The merging of BICs can induce topological charge transition and yield a large wavevector space around theΓpoint with ultra-high quality(Q)factors.Our findings provide a novel degree of freedom for manipulating polarization singularities,which holds great promise in radiation modulation and singular optics.
文摘Correction to:Nano-Micro Lett.(2025)17:24 https://doi.org/10.1007/s40820-024-01515-0 Following publication of the original article[1],the authors reported the author list needed to be updated because the last three author names were duplicated.The correct author list has been provided in this Correction.The original article[1]has been corrected.
基金supported by the National Natural Science Foundation of China(grant number:22274050)the Shanghai Science and Technology Commission(contract number:23J21900300)the Fundamental Research Funds for the Central Universities.
文摘Enhancing the sensitivity of nuclear magnetic resonance(NMR)technology has been the focus of NMR research for decades,which offers the potential to significantly expand its applications in chemistry,biology,and medical imaging.Parahydrogen-induced polarization(PHIP)emerges as a cost-effective approach to substantially enhance the sensitivity of NMR.Nevertheless,the amplification of the ^(1)H signal in PHIP is susceptible to interference from the thermal polarization state ^(1)H NMR signal.Employing RASER(radiofrequency amplification by stimulated emission of radiation)proves effective in mitigating such interference,which can reduce the linewidth and increase the sensitivity at the same time.In this work,we utilized PHIP and RASER to enhance the signal-to-noise ratio(SNR)of a series of biocompatible alkynyl organic acid molecules.The alkynyl acid with the highest enhancement factor was first identified through PASADENA(parahydrogen and synthesis allow dramatically enhanced nuclear alignment)experiments.Subsequently,RASER experiments were carried out through hyperpolarization of 5-hexynoic acid,exploring its signal characteristics under varying flow rates and pressures.The SNR of proton signals of 5-hexynoic acid surpassed 150,000,an 18.62-fold improvement compared with traditional hyperpolarized signals in PASADENA,and a markedly narrowed linewidth of 0.06 Hz.
基金National Natural Science Foundation of China (52372224 and 52072299)Major Project of Shaanxi Coal Joint Fund of Shaanxi Provincial Science and Technology Department (2019JLZ-07)。
文摘Na_(3)V_(2)(PO_(4))_(2)O_(2)F (VP) is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific capacity.Density functional theory (DFT) and finite element simulations show that incorporating SO_(4)^(2-)into VP decreases its band gap,lowers the migration energy barrier,and ensures a uniform Na+concentration gradient and stress distribution during charge and discharge cycles.Consequently,the average Na+diffusion coefficient of Na_(3)V_(2)(PO_(4))_(1.95)(SO_(4))_(0.05)O_(2)F(VPS-1) is roughly double that of VP,leading to enhanced rate capability (80 C,75.5 mAh g^(-1)) and cycling stability (111.0 mAh g^(-1)capacity after 1000 cycles at 10 C current density) for VPS-1.VPS-1 exhibits outstanding fast-charging capabilities,achieving an 80%state of charge in just 8.1 min.The assembled VPS-1//SbSn/NPC full cell demonstrated stable cycling over 200 cycles at a high 5 C current,maintaining an average coulombic efficiency of 95.35%.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074094 and 121774271)the Sino-German Mobility Program of the Sino-German Center for Science Funding(Grant No.M-0225)the Capacity Building for Science&Technology Innovation-Fundamental Scientific Research Funds(Grant No.00820531120017).
文摘Conventionally,the spatially structured light beams produced by metasurfaces primarily highlight the polarization modulation of the beams propagating along the optical axis or the beams'spatial transmission trajectory.In particular,along the optical axis,the polarization state is either constant or varies continuously in each output plane.Here,we develop innovative spatially structured light beams with continually changing polarization along any arbitrary spatial transmission trajectories.With tri-layer metallic metasurfaces,the geometric characteristics of each layer structure can be adjusted to modulate the phase and polarization state of the incident terahertz(THz)wave.The beam will converge to the predefined trajectory along several paths to generate a Bessel-like beam with longitudinal polarization changes.We demonstrate the versatility of the approach by designing two THz-band structured light beams with varying polarization states along the spatial helical transmission trajectory.Continuous linear polarization changes and linear polarization to right circular polarization(RCP)and back to linear polarization changes are realized respectively.The experimental results are basically consistent with the simulated results.Our proposal for arbitrary trajectory structured light beams with longitudinally varying polarization offers a practical method for continuously regulating the characteristics of spatial structured light beams with non-axial transmission.This technique has potential uses in optical encryption,particle manipulation,and biomedical imaging.
文摘A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads to a significant optical loss.The theoretical maximum optical efficiency is merely 25%.To transcend this optical efficiency constraint while retaining the foldable characteristic inherent to traditional pancake optics,in this paper,we propose a theoretically lossless folded optical system to replace the HM with a nonreciprocal polarization rotator.In our feasibility demonstration experiment,we used a commercial Faraday rotator(FR)and reflective polarizers to replace the lossy HM.The theoretically predicted 100%efficiency can be achieved approximately by using two high-extinction-ratio reflective polarizers.In addition,we evaluated the ghost images using a micro-OLED panel in our imaging system.Indeed,the ghost images can be suppressed to undetectable level if the optics are with antireflection coating.Our novel pancake optical system holds great potential for revolutionizing next-generation VR displays with lightweight,compact formfactor,and low power consumption.
基金supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020A1515110905)+1 种基金Guangdong Special Fund for key Areas(20237DZX3042)Shenzhen Stable Support Project and the Fundamental Research Fund of Heilongjiang Provincial University(145309101)。
文摘Homogeneous heterogeneous(heterophase)interfaces regulated with low energy barriers have a fast response to applied electric fields and could provide a unique interfacial polarization,which facilitate the transport of electrons across the substrate.Such regulation on the interfaces is effective in modulating electromagnetic wave absorbing materials.Herein,we construct NbS_(2)–NiS_(2)heterostructures with NiS_(2)nanoparticles uniformly grown in NbS_(2)hollow nanospheres,and such particular structure enhances the interfacial polarization.The strong electron transfer at the interface promotes electron transport throughout the material,which results in less scattering,promotes conduct ion loss and dielectric polarization relaxation,improves dielectric loss,and results in a good impedance matching of the material.Consequently,the absorbing band may be successful tuned.By regulating the amount of NiS_(2),the heterogeneous interface is finely alternated so that the overall wave-absorbing performance is shifted to lower frequencies.With a NiS_(2)content of 15 wt%and an absorber thickness of 1.84 mm,the minimum reflection loss at 14.56 GHz is53.1 dB,and the effective absorption bandwidth is 5.04 GHz;more importantly,the minimum reflection loss in different bands is20 dB,and the microwave energy absorption rate reaches 99%when the thickness is about 1.5–4.5 mm.This work demonstrates the construction of homogeneous heterostructures is effective in improving the electromagnetic absorption properties,providing guideline for the synthesis of highly efficient electromagnetic absorbing materials.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1403203 and 2021YFA1600201)the National Natural Science Foundation of China (Grant No. 12274414)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures (Contract No. JZHKYPT-2021-08)。
文摘Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr_(2) by using combined measurements of the angle-resolved polarized Raman spectroscopy(ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr_(2) flake.And anisotropic optical absorption spectrum of PdBr_(2) nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr_(2) nanowire exhibits high responsivity of 747 A·W^(-1) and specific detectivity of 5.8×10^(12) Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr_(2), establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10225417 and 61675009)the Natural Science Foundation of Beijing Municipality (Grant Nos. 4204091 and KZ201910005006)the China Postdoctoral Science Foundation (Grant No. 212423)。
文摘An all-fiber polarization maintaining high-power laser system operating at 1.7 μm based on the Ramaninduced soliton self-frequency shifting effect is demonstrated. The entirely fiberized system is built by erbiumdoped oscillator and two-stage amplifiers with polarization maintaining commercial silica fibers and devices, which can provide robust and stable soliton generation. High-power soliton laser with the average power of 0.28 W,the repetition rate of 42.7 MHz, and pulse duration of 515 fs is generated directly from the main amplifier.Our experiment provides a feasible method for high-power all-fiber polarization maintaining femtosecond laser generation working at 1.7 μm.
基金financial supports from National Key Research and Development Program of China(2018YFA0701800)Fujian Province Major Science and Technology Program(2020HZ01012)+1 种基金National Natural Science Foundation of China(NSFC)(U22A2080)China Scholarship Council(202109107007).
文摘Orthogonal matrices have become a vital means for coding and signal processing owing to their unique distributional properties.Although orthogonal matrices based on amplitude or phase combinations have been extensively explored,the orthogonal matrix of polarization combinations(OMPC)is a novel,relatively unexplored concept.Herein,we propose a method for constructing OMPCs of any dimension encompassing 4n(where n is 1,2,4,8,…)mutually orthogonal 2ncomponent polarization combinations.In the field of holography,the integration of polarization multiplexing techniques with polarization-sensitive materials is expected to emerge as a groundbreaking approach for multichannel hologram multiplexing,offering considerable enhancements in data storage capacity and security.A multidimensional OMPC enables the realization of multichannel multiplexing and dynamical modulation of information in polarization holographic recording.Despite consolidating all information into a single position within the material,we effectively avoided extraneous crosstalk during the reconstruction process.Our results show that achieving four distinct holographic images individually and simultaneously depends on the polarization combination represented by the incident wave.This discovery opens up a new avenue for achieving highly holographic information storage and dynamically displayed information,harnessing the potential of OMPC to expand the heretofore limited dimensionality of orthogonal polarization.
基金supported by the National Natural Science Foundation of China(Grant Nos.11774303 and 11574373)the financial support from“15th Graduate Research Innovation Project”from Yunnan Universityfinancial support from the Joint Fund of Yunnan Provincial Science and Technology Department(Grant No.2019FY003008)。
文摘For designing low-impedance magnetic tunnel junctions(MTJs),it has been found that tunneling magnetoresistance strongly correlates with the insulating barrier thickness,imposing a fundamental problem about the relationship between spin polarization of ferromagnet and the insulating barrier thickness in MTJs.Here,we investigate the influence of alumina barrier thickness on tunneling spin polarization(TSP)through a combination of theoretical calculations and experimental verification.Our simulating results reveal a significant impact of barrier thickness on TSP,exhibiting an oscillating decay of TSP with the barrier layer thinning.Experimental verification is realized on FeNi/AlO_(x)/Al superconducting tunnel junctions to directly probe the spin polarization of FeNi ferromagnet using Zeeman-split tunneling spectroscopy technique.These findings provide valuable insights for designs of high-performance spintronic devices,particularly in applications such as magnetic random access memories,where precise control over the insulating barrier layer is crucial.
基金supported by the National Natural Science Foundation of China and the Open Project Program of Wuhan National Laboratory for Optoelectronics(Grant No.2022WNLOKF012).
文摘Terahertz polarization conversion devices have significant potential applications in various fields such as terahertzimaging and spectroscopy.In this paper,we utilize genetic algorithms to topologically optimize the metasurface unit cellsand design a reflective linear polarization conversion metasurface with ultra-broadband and wide-angle characteristics.By partitioning the metallic pattern layer into quadrants,the encoding length is effectively reduced,resulting in a shorteroptimization time.The research results indicate that the converter possesses a polarization conversion efficiency ratio higherthan 90%and a relative bandwidth ratio of 125%in a range of 0.231-0.995 THz.Meanwhile,it can maintain excellentpolarization conversion properties when the incident angle of terahertz waves is less than 45°and the polarization angle isless than 15°,demonstrating excellent practicality.New insights are provided for the design of terahertz wide-angle ultrawidebandpolarization conversion devices,and the proposed metasurfce has potential applications in terahertz polarizationimaging,spectroscopy and communication fields.
