Effects of oblique incidence of terahertz waves on the response of planar split-ring resonators are investigated, both experimentally and by simulation. It is found that the incident angle dependent phase delay and co...Effects of oblique incidence of terahertz waves on the response of planar split-ring resonators are investigated, both experimentally and by simulation. It is found that the incident angle dependent phase delay and coupling conditions of neighboring split-ring resonator （SRR） units play important roles and greatly change both the transmission and reflection spectra for the resonant feature of linear charge oscillations. Our results show that the SRR structure-supported magne- toelectric couplings at oblique excitation are trivial and can be ignored. A highly symmetric response is found in the cross-polarization effects, which may manifest the bianisotropic properties of the SRR system but this needs further study.展开更多
An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negati...An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negative （MNG） material is expanded from 3.53% up to 12.87% by adding split-ring resonators （SRRs） and arranging them by proposed steps. Moreover, the experimental results validate the effectiveness of bandwidth-expanding methods, which is promising for the extensive application of metamaterials in the microwave field.展开更多
Metamaterial one-dimensional periodic structures are composed of split-ring resonators, which can display electric permittivity and magnetic permeability simultaneously negative, are studied experimentally. In the pre...Metamaterial one-dimensional periodic structures are composed of split-ring resonators, which can display electric permittivity and magnetic permeability simultaneously negative, are studied experimentally. In the present study, each resonator is made up of two concentric circular copper rings patterned on a substrate of kapton, with slits diametrically opposite each other and with the line of the splits along the longitudinal direction of the periodic array containing seven split rings evenly spaced. The experiments consist in inserting the metamaterial slab into a square waveguide of side length 6 mm, corresponding to a cutoff frequency of 25 GHz. Transmission bands due to magnetic and electrical responses are identified for slits with aperture widths of 1 mm and 2 mm, centered at 5.67 and 6.12 GHz frequencies, respectively, values well below the 25 GHz frequency cutoff, so characterizing a medium with negative permeability and permittivity.展开更多
Novel band-stop filters with circular split-ring resonators based on the metal-insulator-metal （MIM） structure are presented, with their transmission properties of SPPs propagating through the filter simulated by th...Novel band-stop filters with circular split-ring resonators based on the metal-insulator-metal （MIM） structure are presented, with their transmission properties of SPPs propagating through the filter simulated by the finite-difference time-domain （FDTD） method, The variation of the gap of the split ring can affect the transmission characteristics, i.e., the transmission spectrum of SPPs exhibiting a shift, which is useful for modulating the filter. Linear and nonlinear media are used in the resonator respectively. By varying the refractive index of the linear medium, the transmission properties can be changed obviously, and the effect caused by changing the incident intensity with a nonlinear medium is similar. Several resonant modes that are applicable can be enhanced by changing the position of the gap of the split ring. Thus, the transmission properties can be modulated by adjusting the size of the gap, varying the refractive index, and changing the incident intensity of the input light. These methods may play significant roles in applications of optical integrated circuits and nanostructural devices.展开更多
A tunable metamaterial filter is designed based on split-ring resonators(SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loadi...A tunable metamaterial filter is designed based on split-ring resonators(SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loading tunable devices, the continuous operation of the filter is realized at X band(from 10.7 GHz to 12 GHz), the bandwidth is about 13%, the minimum return loss is 35 dB, and the maximum insertion loss is 0.37 d B. The results illustrate that the metamaterial filter shows the compact size, wide bandwidth and good band pass characteristics.展开更多
This Letter proposes a novel method for enhancing terahertz(THz) radiation from microstructure photoconductive antennas(MSPCA). We present two types of MSPCA, which contain split-ring resonators(SRRs) and dipole photo...This Letter proposes a novel method for enhancing terahertz(THz) radiation from microstructure photoconductive antennas(MSPCA). We present two types of MSPCA, which contain split-ring resonators(SRRs) and dipole photoconductive antennas(D-PCAs). The experimental results reveal that when the femtosecond laser is pumping onto the split position of the SRR, the maximum THz radiation power is enhanced by 92 times compared to pumping at the electrode edge of the D-PCA. Two π phase shifts occur as the pumping laser propagates from the negative electrode to the positive electrode. Analysis shows that photoinduced carrier charges move within the split position of the SRR.展开更多
This study investigates the frequency-temperature behaviors in AT-cut quartz crystal resonators(QCRs).First,the dispersion relations of an infinite quartz plate are obtained through a semi-analytical finite element(SA...This study investigates the frequency-temperature behaviors in AT-cut quartz crystal resonators(QCRs).First,the dispersion relations of an infinite quartz plate are obtained through a semi-analytical finite element(SAFE)analysis,which explicitly reveals the intrinsic frequency-temperature dependence of different vibration modes.Subsequently,we address practical resonator configurations by examining finite quartz plates,where numerical simulations uncover critical interactions between the operational thickness-shear(TS)mode and coupling modes,i.e.,the flexure(F),face-shear(FS),and extension(E)modes.Through the frequency spectra analysis,we demonstrate that both the plate aspect ratio and thermal variations affect mode-coupling behaviors.Unstable frequency-temperature variations(activity dips)are observed at critical resonator dimensions.Validation through the free-vibration eigen-frequency analysis and forced-vibration admittance characterization confirms the stable or unstable states predicted by the frequency spectra.The established framework not only reveals the origin of temperatureinduced activity dips but also provides the crucial design criteria for suppressing the mode-coupling interference in high-stability resonators.展开更多
1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(I...1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(IL),and enhancement of upper stopband rejection(Huang et al.,2021;Snyder et al.,2021;Lin et al.,2023;Zeng et al.,2023).展开更多
A polarization-insensitive, square split-ring resonator（SSRR） is simulated and experimented. By investigating the influence of the asymmetrical arm width in typical SSRRs, we find that the variation of the arm width...A polarization-insensitive, square split-ring resonator（SSRR） is simulated and experimented. By investigating the influence of the asymmetrical arm width in typical SSRRs, we find that the variation of the arm width enables a blue shift of the resonance frequency for the 0° polarized wave and a red shift of the resonance frequency for the 90° polarized wave. Thus, the resonance frequency for the 0° polarized wave and the resonance frequency for the 90° polarized wave will be identical by asymmetrically adjusting the arm width of the SSRR. Two modified, split-ring resonators（MSRRs） that are insensitive to the polarization with asymmetrical arm widths are designed, fabricated, and tested. Excellent agreement between the simulations and experiments for the MSRRs demonstrates the polarization insensitivity with asymmetrical arm widths. This work opens new opportunities for the investigation of polarization-insensitive, split-ring resonator metamaterials and will broaden the applications of split-ring resonators in various terahertz devices.展开更多
To use the single split-ring resonator （SRR） as a basic unit cell for small antenna with multi-band frequency response is proposed. The structure of antenna is consisted of a single spilt-ring resonator and a couple...To use the single split-ring resonator （SRR） as a basic unit cell for small antenna with multi-band frequency response is proposed. The structure of antenna is consisted of a single spilt-ring resonator and a coupled microstrip line. The designed antenna is numerically optimized with CST Microwave Studio. The radiation properties of the antenna show that there are three frequency bands among which two bands are 1.3 GHz and 2.1 GHz ultra-widehand （UWB）, respectively, where Sll is less than - 10 dB. The gain at every frequency for the multi-hand antenna is above 2.6 dBi, and it increases monotonously with the frequency in the two UWB.展开更多
Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coup...Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coupled micromechanical resonators,highlighting the latest advancements in four key areas:internal resonance,synchronization,frequency combs,and mode localization.The origin,development,and potential applications of each of these dynamic phenomena within mode-coupled micromechanical systems are investigated,with the goal of inspiring new ideas and directions for researchers in this field.展开更多
The excellent mechanical properties make graphene promising for realizing nanomechanical resonators with high resonant frequencies,large quality factors,strong nonlinearities,and the capability to efectively interface...The excellent mechanical properties make graphene promising for realizing nanomechanical resonators with high resonant frequencies,large quality factors,strong nonlinearities,and the capability to efectively interface with various physical systems.Equipped with gate electrodes,it has been demonstrated that these exceptional device properties can be electrically manipulated,leading to a variety of nanomechanical/acoustic applications.Here,we review the recent progress of graphene nanomechanical resonators with a focus on their electrical tunability.First,we provide an overview of diferent graphene nanomechanical resonators,including their device structures,fabrication methods,and measurement setups.Then,the key mechanical properties of these devices,for example,resonant frequencies,nonlinearities,dissipations,and mode coupling mechanisms,are discussed,with their behaviors upon electrical gating being highlighted.After that,various potential classical/quantum applications based on these graphene nanomechanical resonators are reviewed.Finally,we briefy discuss challenges and opportunities in this feld to ofer future prospects for the ongoing studies on graphene nanomechanical resonators.展开更多
Enhancing the vibration resistance of micro-electro-mechanical systems(MEMS)resonators in complex environments is a critical issue that urgently needs to be addressed.This paper presents a chip-scale locally resonant ...Enhancing the vibration resistance of micro-electro-mechanical systems(MEMS)resonators in complex environments is a critical issue that urgently needs to be addressed.This paper presents a chip-scale locally resonant phononic crystal(LRPnC)plate based on a folded helical beam structure.Through finite element simulation and theoretical analysis,the bandgap characteristics and vibration suppression mechanisms of this structure were thoroughly investigated.The results show that the structure exhibits a complete bandgap in the frequency range of 9.867-14.605 kHz,and the bandgap can be effectively tuned by adjusting the structural parameters.Based on this,the influence of the number of unit cell layers on the vibration reduction performance was further studied,and a finite periodic LRPnC plate was constructed.Numerical studies have shown that the LRPnC plate can achieve more than-30 dB of vibration attenuation within the bandgap and effectively suppress y-direction coupling vibrations caused by x-direction propagating waves.In addition,its chip-scale size and planar structure design provide new ideas and methods for the engineering application of phononic crystal technology in the field of MEMS vibration isolation.展开更多
As an ultrathin wide-bandgap(WBG)material,CaNb_(2)O_(6)exhibits excellent optical and electrical properties.Particularly,its highly asymmetric crystal structure provides new opportunities for designing novel nanodevic...As an ultrathin wide-bandgap(WBG)material,CaNb_(2)O_(6)exhibits excellent optical and electrical properties.Particularly,its highly asymmetric crystal structure provides new opportunities for designing novel nanodevices with directional functionality.However,due to the significant challenges in applying conventional techniques to nanoscale samples,the in-plane anisotropy of CaNb_(2)O_(6)has still remained unexplored.Here,we leverage the resonant nanoelectromechanical systems(NEMS)platform to successfully quantify both the mechanical and thermal anisotropies in such an ultrathin WBG crystal.Specifically,by measuring the dynamic response in both spectral and spatial domains,we determine the anisotropic Young’s modulus of CaNb_(2)O_(6)as E_(Y(a))=70.42 GPa and EY(b)=116.2 GPa.By further expanding this technique to cryogenic temperatures,we unveil the anisotropy in thermal expansion coefficients as α_((a))=13.4 ppm·K^(-1),α(b)=2.9 ppm·K^(-1).Interestingly,through thermal strain engineering,we successfully modulate the mode sequence and achieve a crossing of(1×2)-(2×1)modes with perfect degeneracy.Our study provides guidelines for future CaNb_(2)O_(6)nanodevices with additional degrees of freedom and new device functions.展开更多
A broadband tunable acoustic metasurface(BTAM)is conceived with Helmholtz resonators(HRs).The tunability of HRs’neck enables precise control over the phase shift of the unit cell.Through careful arrangement of unit c...A broadband tunable acoustic metasurface(BTAM)is conceived with Helmholtz resonators(HRs).The tunability of HRs’neck enables precise control over the phase shift of the unit cell.Through careful arrangement of unit cells,the BTAMs are engineered to exhibit various phase differences,thereby inducing anomalous reflections and acoustic focusing.Numerical simulations demonstrate the BTAM’s remarkable efficacy in manipulating the angle of reflection wave and achieving wave focusing across a broadband frequency range.Experimental investigations of the phase shift and anomalous reflection further validate the design of metasurface.This work contributes to the fields of broadband and tunable acoustic wave manipulation and provides a flexible and efficient approach for acoustic control devices.展开更多
Microring resonators(MRRs)are extensively utilized in photonic chips for generating quantum light sources and enabling high-efficiency nonlinear frequency conversion.However,conventional microrings are typically optim...Microring resonators(MRRs)are extensively utilized in photonic chips for generating quantum light sources and enabling high-efficiency nonlinear frequency conversion.However,conventional microrings are typically optimized for a single specific function,limiting their versatility in multifunctional applications.In this work,we propose a reconfigurable microring resonator architecture designed to accommodate diverse application requirements.By integrating a cascaded Mach–Zehnder interferometer(MZI)as the microring coupler,the design enables independent control of the quality factors for pump,signal and idler photons through two tunable phase shifters.This capability allows for dynamic tuning and optimization of critical performance parameters,including photon-pair generation rate(PGR),spectral purity and single photon heralding efficiency(HE).The proposed structure is implemented on a silicon photonic chip,and experimental results exhibit a wide range of tunability for these parameters,with excellent agreement with theoretical predictions.This flexible and multi-functional design offers a promising pathway for high-performance,highly integrated on-chip quantum information processing systems.展开更多
Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of m...Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.展开更多
To enhance the quality factor and sensitivity of refractive index sensors,a feedback waveguide slot grating micro-ring resonator was proposed.An air-hole grating structure was introduced based on the slot micro-ring,u...To enhance the quality factor and sensitivity of refractive index sensors,a feedback waveguide slot grating micro-ring resonator was proposed.An air-hole grating structure was introduced based on the slot micro-ring,utilizing the reflection of the grating to achieve the electromagnetic-like induced transparency effect at different wavelengths.The high slope characteristics of the EIT-like effect enabled a higher quality factor and sensitivity.The transmission principle of the structure was analyzed using the transmission matrix method,and the transmission spectrum and mode field distribution were simulated using the finite-difference time-domain(FDTD)method,and the device structure parameters were adjusted for optimization.Simulation results show that the proposed structure achieves an EIT-like effect with a quality factor of 59267.5.In the analysis of refractive index sensing characteristics,the structure exhibits a sensitivity of 408.57 nm/RIU and a detection limit of 6.23×10^(-5) RIU.Therefore,the proposed structure achieved both a high quality factor and refractive index sensitivity,demonstrating excellent sensing performance for applications in environmental monitoring,biomedical fields,and other areas with broad market potential.展开更多
This article investigates the second overtone thickness-extensional(TE2)vibrations and associated mode-coupling behaviors in ZnO piezoelectric film bulk acoustic resonator(FBAR),utilizing its wave dispersion relation ...This article investigates the second overtone thickness-extensional(TE2)vibrations and associated mode-coupling behaviors in ZnO piezoelectric film bulk acoustic resonator(FBAR),utilizing its wave dispersion relation and the higher-order stress balance principle.By superimposing the general wave solutions of multiple eigenmodes within the frequency range of the TE2 mode,mode-coupling solutions for ZnO FBAR are constructed.The substitution of these mode-coupling solutions into the higher-order stress balance principle,as laterally weak boundary conditions,leads to the frequency spectrogram equation,determining the relationship between resonance frequency and plate length-to-thickness ratio.A modified algorithm that combines the bisection method and the complex modulus ratio method is developed to solve the dispersion equation and frequency spectrogram equation(namely a kind of 2D complex transcendental equations)accurately and efficiently.The obtained results indicate that the operational TE2 mode may couple to unwanted 3^(rd)thickness-shear,fundamental thickness-shear,and flexural modes.Moreover,the mode-coupling behaviors depend strongly on resonance frequencies and plate length-to-thickness ratio.The displacement distributions of total displacement components,alongside the main displacement com-ponents of all considered eigenmodes,clearly demonstrate the variety of coupling behaviors.According to the obtained frequency spectrograms,the desirable values of plate length-to-thickness ratio for a clean operating mode with very weak coupling intensity are determined.These findings are of vital importance for the understanding of the mode-coupling me-chanism in overtone thickness-extensional FBARs,which will facilitate the structural design and optimization of FBAR devices.展开更多
Unlocking the full potential of integrated photonics requires versatile,multi-functional devices that can adapt to diverse application demands.However,confronting this challenge with conventional singlefunction resona...Unlocking the full potential of integrated photonics requires versatile,multi-functional devices that can adapt to diverse application demands.However,confronting this challenge with conventional singlefunction resonators often results in cumbersome system designs.We present an elegant solution:a versatile and reconfigurable dual-polarization Si_(3)N_(4)microresonator that represents a new perspective in on-chip photonic designs.Our device can be dynamically reconfigured into three distinct topologies:a Möbius-like microcavity,a Fabry-Pérot resonator,and a microring resonator.This unprecedented functionality is enabled by a tunable balanced Mach-Zehnder interferometer that facilitates controllable mutual mode coupling of counterpropagating light using a single control knob.We experimentally demonstrate that the device not only supports polarization-diverse operation on a compact footprint but also gives rise to a wide variety of physical phenomena,including a standing wave cavity,a traveling wave cavity,free spectral range multiplication,and the photonic pinning effect.These behaviors are accurately modeled using the transfer matrix method and intuitively explained by the temporal coupled-mode theory.Our results underscore the potential for a chip-scale platform to realize reconfigurable reconstructive spectrometers and on-chip synthetic dimensions for topological physics.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2014CB339800)the National Natural Science Foundation of China(Grant Nos.11374358 and 61077082)
文摘Effects of oblique incidence of terahertz waves on the response of planar split-ring resonators are investigated, both experimentally and by simulation. It is found that the incident angle dependent phase delay and coupling conditions of neighboring split-ring resonator （SRR） units play important roles and greatly change both the transmission and reflection spectra for the resonant feature of linear charge oscillations. Our results show that the SRR structure-supported magne- toelectric couplings at oblique excitation are trivial and can be ignored. A highly symmetric response is found in the cross-polarization effects, which may manifest the bianisotropic properties of the SRR system but this needs further study.
基金Project supported partially by the National Natural Science Foundation of China (Grant Nos. 60872034 and 60971029)the New-Century Talent Program of the Education Department of China (Grant No. NCET070154)+1 种基金the National Defense Research Funding (Grant No. ZJ10DZ02111)the Hi-Tech Research and Development Program of China (Grant No. 2009AA01Z231)
文摘An effective approach to expand the bandwidth of negative permeability of small-sized planax materials is proposed. Based on qualitative analysis of equivalent circuit models, the fractional bandwidth of an μ-negative （MNG） material is expanded from 3.53% up to 12.87% by adding split-ring resonators （SRRs） and arranging them by proposed steps. Moreover, the experimental results validate the effectiveness of bandwidth-expanding methods, which is promising for the extensive application of metamaterials in the microwave field.
基金supported by FAPESP(Sao Paulo Research Foundation)and CNPq(National Council for Scientific and Technological Development)in Brazil
文摘Metamaterial one-dimensional periodic structures are composed of split-ring resonators, which can display electric permittivity and magnetic permeability simultaneously negative, are studied experimentally. In the present study, each resonator is made up of two concentric circular copper rings patterned on a substrate of kapton, with slits diametrically opposite each other and with the line of the splits along the longitudinal direction of the periodic array containing seven split rings evenly spaced. The experiments consist in inserting the metamaterial slab into a square waveguide of side length 6 mm, corresponding to a cutoff frequency of 25 GHz. Transmission bands due to magnetic and electrical responses are identified for slits with aperture widths of 1 mm and 2 mm, centered at 5.67 and 6.12 GHz frequencies, respectively, values well below the 25 GHz frequency cutoff, so characterizing a medium with negative permeability and permittivity.
基金supported by the National Natural Science Foundation of China(Grant No.61001018)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2011FM009 and ZR2012FM011)+3 种基金the Research Fund of Shandong University of Science and Technology(SDUST),China(Grant No.2010KYJQ103)the SDUST Research Fund,China(Grant No.2012KYTD103)the Shandong Province Higher Educational Science and Technology Program,China(Grant No.J11LG20)the Qingdao Economic&Technical Development Zone Science&Technology Project,China(Grant No.2013-1-64)
文摘Novel band-stop filters with circular split-ring resonators based on the metal-insulator-metal （MIM） structure are presented, with their transmission properties of SPPs propagating through the filter simulated by the finite-difference time-domain （FDTD） method, The variation of the gap of the split ring can affect the transmission characteristics, i.e., the transmission spectrum of SPPs exhibiting a shift, which is useful for modulating the filter. Linear and nonlinear media are used in the resonator respectively. By varying the refractive index of the linear medium, the transmission properties can be changed obviously, and the effect caused by changing the incident intensity with a nonlinear medium is similar. Several resonant modes that are applicable can be enhanced by changing the position of the gap of the split ring. Thus, the transmission properties can be modulated by adjusting the size of the gap, varying the refractive index, and changing the incident intensity of the input light. These methods may play significant roles in applications of optical integrated circuits and nanostructural devices.
基金supported by the Key Laboratory Foundation of China Electronics Technology Group Corporation(No.ZX15ZS391)the National Fund for International Cooperation in Science and Technology(No.2014DFR10020)the Natural Science Foundation of Shanxi Province(Nos.2014021020-1 and 2015021083)
文摘A tunable metamaterial filter is designed based on split-ring resonators(SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loading tunable devices, the continuous operation of the filter is realized at X band(from 10.7 GHz to 12 GHz), the bandwidth is about 13%, the minimum return loss is 35 dB, and the maximum insertion loss is 0.37 d B. The results illustrate that the metamaterial filter shows the compact size, wide bandwidth and good band pass characteristics.
基金supported by the National Natural Science Foundation of China (No. 11872058)the National Defense Basic Scientific Research Program of China (Nos. JCKY2018404C007,JSZL2017404A001,and JSZL2018204C002)the Sichuan Science and Technology Program of China (No. 2019YFG0114)。
文摘This Letter proposes a novel method for enhancing terahertz(THz) radiation from microstructure photoconductive antennas(MSPCA). We present two types of MSPCA, which contain split-ring resonators(SRRs) and dipole photoconductive antennas(D-PCAs). The experimental results reveal that when the femtosecond laser is pumping onto the split position of the SRR, the maximum THz radiation power is enhanced by 92 times compared to pumping at the electrode edge of the D-PCA. Two π phase shifts occur as the pumping laser propagates from the negative electrode to the positive electrode. Analysis shows that photoinduced carrier charges move within the split position of the SRR.
基金Project supported by the National Key Research and Development Program of China(No.2023YFE0111000)the National Natural Science Foundation of China(Nos.12102183,12172171,and U24A2005)the Shenzhen Science and Technology Program of China(No.JCYJ20230807142004009)。
文摘This study investigates the frequency-temperature behaviors in AT-cut quartz crystal resonators(QCRs).First,the dispersion relations of an infinite quartz plate are obtained through a semi-analytical finite element(SAFE)analysis,which explicitly reveals the intrinsic frequency-temperature dependence of different vibration modes.Subsequently,we address practical resonator configurations by examining finite quartz plates,where numerical simulations uncover critical interactions between the operational thickness-shear(TS)mode and coupling modes,i.e.,the flexure(F),face-shear(FS),and extension(E)modes.Through the frequency spectra analysis,we demonstrate that both the plate aspect ratio and thermal variations affect mode-coupling behaviors.Unstable frequency-temperature variations(activity dips)are observed at critical resonator dimensions.Validation through the free-vibration eigen-frequency analysis and forced-vibration admittance characterization confirms the stable or unstable states predicted by the frequency spectra.The established framework not only reveals the origin of temperatureinduced activity dips but also provides the crucial design criteria for suppressing the mode-coupling interference in high-stability resonators.
基金supported by the National Natural Science Foundation of China(No.62371263)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCK25_1995).
文摘1 Introduction Recently,the increasing demand for advanced telecommunication systems has spurred extensive research into bandpass filters(BPFs),with particular emphasis on miniaturization,reduction of insertion loss(IL),and enhancement of upper stopband rejection(Huang et al.,2021;Snyder et al.,2021;Lin et al.,2023;Zeng et al.,2023).
基金supported by the National High Technology Research and Development Program of China (No. 2011AA010204)the National Natural Science Foundation of China (Nos. 91438118 and 61370011)the Fundamental Research Funds for the Central Universities of China (No. ZYGX2014J037)
文摘A polarization-insensitive, square split-ring resonator（SSRR） is simulated and experimented. By investigating the influence of the asymmetrical arm width in typical SSRRs, we find that the variation of the arm width enables a blue shift of the resonance frequency for the 0° polarized wave and a red shift of the resonance frequency for the 90° polarized wave. Thus, the resonance frequency for the 0° polarized wave and the resonance frequency for the 90° polarized wave will be identical by asymmetrically adjusting the arm width of the SSRR. Two modified, split-ring resonators（MSRRs） that are insensitive to the polarization with asymmetrical arm widths are designed, fabricated, and tested. Excellent agreement between the simulations and experiments for the MSRRs demonstrates the polarization insensitivity with asymmetrical arm widths. This work opens new opportunities for the investigation of polarization-insensitive, split-ring resonator metamaterials and will broaden the applications of split-ring resonators in various terahertz devices.
基金Sponsored by the BIT Developing Foundation(1070050320726)
文摘To use the single split-ring resonator （SRR） as a basic unit cell for small antenna with multi-band frequency response is proposed. The structure of antenna is consisted of a single spilt-ring resonator and a coupled microstrip line. The designed antenna is numerically optimized with CST Microwave Studio. The radiation properties of the antenna show that there are three frequency bands among which two bands are 1.3 GHz and 2.1 GHz ultra-widehand （UWB）, respectively, where Sll is less than - 10 dB. The gain at every frequency for the multi-hand antenna is above 2.6 dBi, and it increases monotonously with the frequency in the two UWB.
基金supported by the National Key Research and Development Program of China(No.2022YFB3203600)the National Natural Science Foundation of China(Nos.12202355,12132013,and 12172323)the Zhejiang Provincial Natural Science Foundation of China(No.LZ22A020003)。
文摘Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coupled micromechanical resonators,highlighting the latest advancements in four key areas:internal resonance,synchronization,frequency combs,and mode localization.The origin,development,and potential applications of each of these dynamic phenomena within mode-coupled micromechanical systems are investigated,with the goal of inspiring new ideas and directions for researchers in this field.
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK20240123)the National Key Research and Development Program of China(Grant No.2022YFA1405900)the National Natural Science Foundation of China(Grant Nos.12274397,12274401,and 12034018)。
文摘The excellent mechanical properties make graphene promising for realizing nanomechanical resonators with high resonant frequencies,large quality factors,strong nonlinearities,and the capability to efectively interface with various physical systems.Equipped with gate electrodes,it has been demonstrated that these exceptional device properties can be electrically manipulated,leading to a variety of nanomechanical/acoustic applications.Here,we review the recent progress of graphene nanomechanical resonators with a focus on their electrical tunability.First,we provide an overview of diferent graphene nanomechanical resonators,including their device structures,fabrication methods,and measurement setups.Then,the key mechanical properties of these devices,for example,resonant frequencies,nonlinearities,dissipations,and mode coupling mechanisms,are discussed,with their behaviors upon electrical gating being highlighted.After that,various potential classical/quantum applications based on these graphene nanomechanical resonators are reviewed.Finally,we briefy discuss challenges and opportunities in this feld to ofer future prospects for the ongoing studies on graphene nanomechanical resonators.
基金supported by National Natural Science Foundation of China(No.62271262).
文摘Enhancing the vibration resistance of micro-electro-mechanical systems(MEMS)resonators in complex environments is a critical issue that urgently needs to be addressed.This paper presents a chip-scale locally resonant phononic crystal(LRPnC)plate based on a folded helical beam structure.Through finite element simulation and theoretical analysis,the bandgap characteristics and vibration suppression mechanisms of this structure were thoroughly investigated.The results show that the structure exhibits a complete bandgap in the frequency range of 9.867-14.605 kHz,and the bandgap can be effectively tuned by adjusting the structural parameters.Based on this,the influence of the number of unit cell layers on the vibration reduction performance was further studied,and a finite periodic LRPnC plate was constructed.Numerical studies have shown that the LRPnC plate can achieve more than-30 dB of vibration attenuation within the bandgap and effectively suppress y-direction coupling vibrations caused by x-direction propagating waves.In addition,its chip-scale size and planar structure design provide new ideas and methods for the engineering application of phononic crystal technology in the field of MEMS vibration isolation.
基金supported by the National Key R&D Program of China(2022YFB3203600)the National Natural Science Foundation of China(Grant Nos.T2325007,62450003,62401104,62404029,U21A20459,62250073,61774029,and U23A20570)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.GZB20230107 and GZB20240109)the Natural Science Foundation of Sichuan Province(Grant Nos.2024NSFSC1430 and 2024NSFSC1408).
文摘As an ultrathin wide-bandgap(WBG)material,CaNb_(2)O_(6)exhibits excellent optical and electrical properties.Particularly,its highly asymmetric crystal structure provides new opportunities for designing novel nanodevices with directional functionality.However,due to the significant challenges in applying conventional techniques to nanoscale samples,the in-plane anisotropy of CaNb_(2)O_(6)has still remained unexplored.Here,we leverage the resonant nanoelectromechanical systems(NEMS)platform to successfully quantify both the mechanical and thermal anisotropies in such an ultrathin WBG crystal.Specifically,by measuring the dynamic response in both spectral and spatial domains,we determine the anisotropic Young’s modulus of CaNb_(2)O_(6)as E_(Y(a))=70.42 GPa and EY(b)=116.2 GPa.By further expanding this technique to cryogenic temperatures,we unveil the anisotropy in thermal expansion coefficients as α_((a))=13.4 ppm·K^(-1),α(b)=2.9 ppm·K^(-1).Interestingly,through thermal strain engineering,we successfully modulate the mode sequence and achieve a crossing of(1×2)-(2×1)modes with perfect degeneracy.Our study provides guidelines for future CaNb_(2)O_(6)nanodevices with additional degrees of freedom and new device functions.
基金supported by the National Natural Science Foundation of China(Grant Nos.11991030,11991031 and 12202054)Aeronautical Science Foundation(Grant No.ASFC20230042072010).
文摘A broadband tunable acoustic metasurface(BTAM)is conceived with Helmholtz resonators(HRs).The tunability of HRs’neck enables precise control over the phase shift of the unit cell.Through careful arrangement of unit cells,the BTAMs are engineered to exhibit various phase differences,thereby inducing anomalous reflections and acoustic focusing.Numerical simulations demonstrate the BTAM’s remarkable efficacy in manipulating the angle of reflection wave and achieving wave focusing across a broadband frequency range.Experimental investigations of the phase shift and anomalous reflection further validate the design of metasurface.This work contributes to the fields of broadband and tunable acoustic wave manipulation and provides a flexible and efficient approach for acoustic control devices.
基金Project supported by the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301500)the National Natural Science Foundation of China(Grant No.62105366)。
文摘Microring resonators(MRRs)are extensively utilized in photonic chips for generating quantum light sources and enabling high-efficiency nonlinear frequency conversion.However,conventional microrings are typically optimized for a single specific function,limiting their versatility in multifunctional applications.In this work,we propose a reconfigurable microring resonator architecture designed to accommodate diverse application requirements.By integrating a cascaded Mach–Zehnder interferometer(MZI)as the microring coupler,the design enables independent control of the quality factors for pump,signal and idler photons through two tunable phase shifters.This capability allows for dynamic tuning and optimization of critical performance parameters,including photon-pair generation rate(PGR),spectral purity and single photon heralding efficiency(HE).The proposed structure is implemented on a silicon photonic chip,and experimental results exhibit a wide range of tunability for these parameters,with excellent agreement with theoretical predictions.This flexible and multi-functional design offers a promising pathway for high-performance,highly integrated on-chip quantum information processing systems.
基金supported by the National Natural Science Foundation of China(Grant No.52175552)the National Key RD Program of China(Grant Nos.2022YFB3205400 and 2022YFB3204300).
文摘Two-dimensional phononic crystal(PnC)slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators(LVRs)through topology optimization.However,the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision,and the anisotropic nature of silicon is frequently overlooked.To address these issues,this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs.The optimized square-lattice PnC slabs,featuring a rounded-cross structure oriented along the`110e directions of silicon,achieve an impressive relative bandgap(RBG)width of 82.2%for in-plane modes.When further tilted by 15° from the (100) directions within the(001)plane,the optimal RBG width is expanded to 91.4%.We fabricate and characterize thin-film piezoelectric-on-silicon LVRs,with or without optimized 2D PnC slabs.The presence of PnC slabs around anchors increases the series and parallel quality factors Q_(s) and Q_(p) from 2240 to 7118 and from 2237 to 7501,respectively,with the PnC slabs oriented along the`110e directions of silicon.
基金supported by Natural Science Foundation of Gansu Province(NO.21JR7RA289)。
文摘To enhance the quality factor and sensitivity of refractive index sensors,a feedback waveguide slot grating micro-ring resonator was proposed.An air-hole grating structure was introduced based on the slot micro-ring,utilizing the reflection of the grating to achieve the electromagnetic-like induced transparency effect at different wavelengths.The high slope characteristics of the EIT-like effect enabled a higher quality factor and sensitivity.The transmission principle of the structure was analyzed using the transmission matrix method,and the transmission spectrum and mode field distribution were simulated using the finite-difference time-domain(FDTD)method,and the device structure parameters were adjusted for optimization.Simulation results show that the proposed structure achieves an EIT-like effect with a quality factor of 59267.5.In the analysis of refractive index sensing characteristics,the structure exhibits a sensitivity of 408.57 nm/RIU and a detection limit of 6.23×10^(-5) RIU.Therefore,the proposed structure achieved both a high quality factor and refractive index sensitivity,demonstrating excellent sensing performance for applications in environmental monitoring,biomedical fields,and other areas with broad market potential.
基金supported by the National Natural Science Foundation of China(Grant Nos.12192210,12192211,12102183,12302200,and 12402192)the Natural Science Foundation of Zhejiang Province(Grant No.LD21A020001)+2 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20230873)the National Postdoctoral Program for Innovation Talents(Grant No.BX2021261)supported by the specialized research projects of Huanjiang Laboratory,Zhuji,Zhejiang Province.
文摘This article investigates the second overtone thickness-extensional(TE2)vibrations and associated mode-coupling behaviors in ZnO piezoelectric film bulk acoustic resonator(FBAR),utilizing its wave dispersion relation and the higher-order stress balance principle.By superimposing the general wave solutions of multiple eigenmodes within the frequency range of the TE2 mode,mode-coupling solutions for ZnO FBAR are constructed.The substitution of these mode-coupling solutions into the higher-order stress balance principle,as laterally weak boundary conditions,leads to the frequency spectrogram equation,determining the relationship between resonance frequency and plate length-to-thickness ratio.A modified algorithm that combines the bisection method and the complex modulus ratio method is developed to solve the dispersion equation and frequency spectrogram equation(namely a kind of 2D complex transcendental equations)accurately and efficiently.The obtained results indicate that the operational TE2 mode may couple to unwanted 3^(rd)thickness-shear,fundamental thickness-shear,and flexural modes.Moreover,the mode-coupling behaviors depend strongly on resonance frequencies and plate length-to-thickness ratio.The displacement distributions of total displacement components,alongside the main displacement com-ponents of all considered eigenmodes,clearly demonstrate the variety of coupling behaviors.According to the obtained frequency spectrograms,the desirable values of plate length-to-thickness ratio for a clean operating mode with very weak coupling intensity are determined.These findings are of vital importance for the understanding of the mode-coupling me-chanism in overtone thickness-extensional FBARs,which will facilitate the structural design and optimization of FBAR devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.62105061,12374301,and 62225404)the Jiangsu Provincial Frontier Technology Research and Development Program(Grant No.BF2024070)+1 种基金the National Key R&D Program of China(Grant No.2024YFA1210500)the Key Lab of Modern Optical Technologies of Education,Ministry of China,Soochow University。
文摘Unlocking the full potential of integrated photonics requires versatile,multi-functional devices that can adapt to diverse application demands.However,confronting this challenge with conventional singlefunction resonators often results in cumbersome system designs.We present an elegant solution:a versatile and reconfigurable dual-polarization Si_(3)N_(4)microresonator that represents a new perspective in on-chip photonic designs.Our device can be dynamically reconfigured into three distinct topologies:a Möbius-like microcavity,a Fabry-Pérot resonator,and a microring resonator.This unprecedented functionality is enabled by a tunable balanced Mach-Zehnder interferometer that facilitates controllable mutual mode coupling of counterpropagating light using a single control knob.We experimentally demonstrate that the device not only supports polarization-diverse operation on a compact footprint but also gives rise to a wide variety of physical phenomena,including a standing wave cavity,a traveling wave cavity,free spectral range multiplication,and the photonic pinning effect.These behaviors are accurately modeled using the transfer matrix method and intuitively explained by the temporal coupled-mode theory.Our results underscore the potential for a chip-scale platform to realize reconfigurable reconstructive spectrometers and on-chip synthetic dimensions for topological physics.
