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
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
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
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
We demonstrate micromachined reconfigurable metamaterials working at multiple frequencies simultaneously in the terahertz range.The proposed metamaterial structures can be structurally reconfigured by employing flexib...We demonstrate micromachined reconfigurable metamaterials working at multiple frequencies simultaneously in the terahertz range.The proposed metamaterial structures can be structurally reconfigured by employing flexible microelectromechanical system-based cantilevers in the resonators,which are designed to deform out of plane under an external stimulus.The proposed metamaterial structures provide not only multiband resonance frequency operation but also polarization-dependent tunability.Three kinds of metamaterials are investigated as electric split-ring resonator(eSRR)arrays with different positions of the split.By moving the position of the split away from the resonator’s center,the eSRR exhibits anisotropy,with the dipole resonance splitting into two resonances.The dipole–dipole coupling strength can be continuously adjusted,which enables the electromagnetic response to be tailored by adjusting the direct current(DC)voltage between the released cantilevers and the silicon substrate.The observed tunability of the eSRRs is found to be dependent on the polarization of the incident terahertz wave.This polarization-dependent tunability is demonstrated by both experimental measurements and electromagnetic simulations.展开更多
Transmission spectroscopy of two Nb double superconducting split-ring samples with different thicknesses on MgO substrates was measured by a continuous Tera-Hertz spectrometer.The transmission curves of two different ...Transmission spectroscopy of two Nb double superconducting split-ring samples with different thicknesses on MgO substrates was measured by a continuous Tera-Hertz spectrometer.The transmission curves of two different samples with the thicknesses of 50 and 150 nm at 7.5 K show dips at 480,545 GHz,respectively,which origin from the different capacities and inductances of the samples.For the sample of 50 nm,the dip shifts to lower frequency,also decreases in depth and increases in width with temperature or field increasing below T c of Nb film,while the sample of 150 nm does not show such a phenomenon.This thickness-dependent transmission behavior is due to the kinetic inductance and conductivity change of superfluid electrons in Nb film and may suggest a practical tunable THz filter based on the thinner samples.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
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
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
Silicon-based microring resonator sensors are promising components for lab-on-chip sensing systems.However,developing a microring resonator sensor with both high sensitivity and wide detectable range has remained chal...Silicon-based microring resonator sensors are promising components for lab-on-chip sensing systems.However,developing a microring resonator sensor with both high sensitivity and wide detectable range has remained challenging.Here,we experimentally demonstrate a high-sensitivity and wide-range subwavelength grating microring resonator sensor by leveraging its dispersion properties.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
Passive Kerr fiber-loop resonators driven by coherent lasers exhibit a variety of nonlinear states,including modulation instability(MI),localized dissipative structures(solitons),and chaos.Although these transitions h...Passive Kerr fiber-loop resonators driven by coherent lasers exhibit a variety of nonlinear states,including modulation instability(MI),localized dissipative structures(solitons),and chaos.Although these transitions have been predicted theoretically,experimental real-time observations are rare in coherently driven Kerr fiber-loop resonators.In this study,we observed real-time transitions between the predicted nonlinear states by sweeping detuning both positively and negatively.We discovered the transition path between nonlinear states depending on the direction of detuning,providing new insights into the nonlinear dynamics.Our findings directly validate theoretical predictions and offer potential implications for future nonlinear optical applications.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
The enhancement of the microcavity quality factor contributes to fundamental linewidth reduction in microcavity lasers.This study demonstrates silica microrod resonators with quality factors approaching 10^(9),fabrica...The enhancement of the microcavity quality factor contributes to fundamental linewidth reduction in microcavity lasers.This study demonstrates silica microrod resonators with quality factors approaching 10^(9),fabricated by CO_(2)laser reflow technology.To improve practical applicability,low-loss package techniques were developed,yielding packaged resonators with optimized optical performance.Using this platform,stimulated Raman lasing was achieved with a pump mode Q-factor of 1.333×10^(9),exhibiting a threshold of 0.765 mW.The laser output stability was characterized by a standard deviation of 0.671 mV over 45 minutes of operation,with corresponding Allan deviation analysis.At the maximum output power of 106.4μW,the measured frequency noise spectral density reached 0.46 Hz~2/Hz,corresponding to a linewidth of 2.89 Hz.Thermal tuning of the packaged module achieved a wavelength shift of 0.206 nm,with a temperature sensitivity of 8.92 pm/℃.This work establishes a new technical pathway for developing compact narrow-linewidth lasers,showing significant potential for medical diagnostics,optical communications,and defense applications.展开更多
Aging,as an inherent stage of life processes,has always been a core research focus in life sciences.Current studies confirm that the accumulation of intracellular molecular damage is a key driver of aging.As protectiv...Aging,as an inherent stage of life processes,has always been a core research focus in life sciences.Current studies confirm that the accumulation of intracellular molecular damage is a key driver of aging.As protective structures at chromosome ends,telomeres exhibit direct correlations between their length and stability and cellular aging processes,disease risks,and lifespan.This article systematically reviews the structural functions of telomeres and their relationship with aging,with particular emphasis on telomere rejuvenation strategies based on electromagnetic radiation techniques.Key experimental approaches include Gavich's mitotic radiation,Composite Wave Resonator(CWRT),and modern telomere length intervention trials.By synthesizing the latest domestic and international research findings,this paper analyzes the feasibility and limitations of these technologies while exploring their potential applications in anti-aging research,providing theoretical references for future studies.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
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 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This work was supported by MOE2012-T2-2-154(Monolithic Integrated Si/AIN Nanophotonics Platform for Optical NEMS and OEICs)under WBS No.R-263-000-A59-112.
文摘We demonstrate micromachined reconfigurable metamaterials working at multiple frequencies simultaneously in the terahertz range.The proposed metamaterial structures can be structurally reconfigured by employing flexible microelectromechanical system-based cantilevers in the resonators,which are designed to deform out of plane under an external stimulus.The proposed metamaterial structures provide not only multiband resonance frequency operation but also polarization-dependent tunability.Three kinds of metamaterials are investigated as electric split-ring resonator(eSRR)arrays with different positions of the split.By moving the position of the split away from the resonator’s center,the eSRR exhibits anisotropy,with the dipole resonance splitting into two resonances.The dipole–dipole coupling strength can be continuously adjusted,which enables the electromagnetic response to be tailored by adjusting the direct current(DC)voltage between the released cantilevers and the silicon substrate.The observed tunability of the eSRRs is found to be dependent on the polarization of the incident terahertz wave.This polarization-dependent tunability is demonstrated by both experimental measurements and electromagnetic simulations.
基金supported by the Science Foundation of the Chinese Academy of Sciences (Grant No.KJCX2-SW-W20)the National Basic Research Program of China (Grant No.2011CB921702)
文摘Transmission spectroscopy of two Nb double superconducting split-ring samples with different thicknesses on MgO substrates was measured by a continuous Tera-Hertz spectrometer.The transmission curves of two different samples with the thicknesses of 50 and 150 nm at 7.5 K show dips at 480,545 GHz,respectively,which origin from the different capacities and inductances of the samples.For the sample of 50 nm,the dip shifts to lower frequency,also decreases in depth and increases in width with temperature or field increasing below T c of Nb film,while the sample of 150 nm does not show such a phenomenon.This thickness-dependent transmission behavior is due to the kinetic inductance and conductivity change of superfluid electrons in Nb film and may suggest a practical tunable THz filter based on the thinner samples.
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National Key Research and Development Program of China(2022YFB2803600)National Natural Science Foundation of China(61905022,62175080)+3 种基金Department of Science and Technology of Jilin Province(20240101338JC)Songshan Lake Materials Laboratory(2023SLABFK11)Science and Technology Planning Project of Shenzhen Municipality(CJGJZD20220517141202005)Hubei Provincial Program for Outstanding Young Talents。
文摘Silicon-based microring resonator sensors are promising components for lab-on-chip sensing systems.However,developing a microring resonator sensor with both high sensitivity and wide detectable range has remained challenging.Here,we experimentally demonstrate a high-sensitivity and wide-range subwavelength grating microring resonator sensor by leveraging its dispersion properties.
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Project supported by the National Natural Science Foundation of China(Grant Nos.12475006 and 12004309)the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.22JSQ036)。
文摘Passive Kerr fiber-loop resonators driven by coherent lasers exhibit a variety of nonlinear states,including modulation instability(MI),localized dissipative structures(solitons),and chaos.Although these transitions have been predicted theoretically,experimental real-time observations are rare in coherently driven Kerr fiber-loop resonators.In this study,we observed real-time transitions between the predicted nonlinear states by sweeping detuning both positively and negatively.We discovered the transition path between nonlinear states depending on the direction of detuning,providing new insights into the nonlinear dynamics.Our findings directly validate theoretical predictions and offer potential implications for future nonlinear optical applications.
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supported by the National Natural Science Foundation of China(Grant Nos.12474372,12474429,62222515,and 12174438)the National Key Research and Development Program of China(Grant Nos.2023YFB2805600 and 2023YFB2806200)+1 种基金the Natural Science Foundation of Beijing Municipality(Grant No.Z210004)the Fund from the State Key Laboratory of Information Photonics and Optical Communications(Grant No.IPOC2024ZR01)。
文摘The enhancement of the microcavity quality factor contributes to fundamental linewidth reduction in microcavity lasers.This study demonstrates silica microrod resonators with quality factors approaching 10^(9),fabricated by CO_(2)laser reflow technology.To improve practical applicability,low-loss package techniques were developed,yielding packaged resonators with optimized optical performance.Using this platform,stimulated Raman lasing was achieved with a pump mode Q-factor of 1.333×10^(9),exhibiting a threshold of 0.765 mW.The laser output stability was characterized by a standard deviation of 0.671 mV over 45 minutes of operation,with corresponding Allan deviation analysis.At the maximum output power of 106.4μW,the measured frequency noise spectral density reached 0.46 Hz~2/Hz,corresponding to a linewidth of 2.89 Hz.Thermal tuning of the packaged module achieved a wavelength shift of 0.206 nm,with a temperature sensitivity of 8.92 pm/℃.This work establishes a new technical pathway for developing compact narrow-linewidth lasers,showing significant potential for medical diagnostics,optical communications,and defense applications.
文摘Aging,as an inherent stage of life processes,has always been a core research focus in life sciences.Current studies confirm that the accumulation of intracellular molecular damage is a key driver of aging.As protective structures at chromosome ends,telomeres exhibit direct correlations between their length and stability and cellular aging processes,disease risks,and lifespan.This article systematically reviews the structural functions of telomeres and their relationship with aging,with particular emphasis on telomere rejuvenation strategies based on electromagnetic radiation techniques.Key experimental approaches include Gavich's mitotic radiation,Composite Wave Resonator(CWRT),and modern telomere length intervention trials.By synthesizing the latest domestic and international research findings,this paper analyzes the feasibility and limitations of these technologies while exploring their potential applications in anti-aging research,providing theoretical references for future studies.
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.
