A wide terahertz tuning range from 0.96 THz to 7.01 THz has been demonstrated based on ring-cavity THz wave parametric oscillator with a KTiOPO_(4)(KTP)crystal.The tuning range was observed intermittently from 0.96 TH...A wide terahertz tuning range from 0.96 THz to 7.01 THz has been demonstrated based on ring-cavity THz wave parametric oscillator with a KTiOPO_(4)(KTP)crystal.The tuning range was observed intermittently from 0.96 THz to 1.87 THz,from 3.04 THz to 3.33 THz,from 4.17 THz to 4.48 THz,from 4.78 THz to 4.97 THz,from 5.125 THz to 5.168 THz,from5.44 THz to 5.97 THz,and from 6.74 THz to 7.01 THz.The dual-Stokes wavelengths resonance phenomena were observed in some certain tuning angle ranges.Through the theoretical analysis of the dispersion curve of the KTP crystal,the intermittent THz wave tuning range and dual-wavelength Stokes waves operation during angle tuning process were explained.The theoretical analysis was in good agreement with the experiment results.The maximum THz output voltage detected by Golay cell was 1.7 V at 5.7 THz under the pump energy of 210 mJ,corresponding to the THz wave output energy of5.47μJ and conversion efficiency of 2.6×10^(-5).展开更多
The optical properties of cylindrical core–shell nanorods(CCSNs)are theoretically investigated in this paper.The results show that Fano resonance can be generated in CCSNs,and the wavelength and the intensity at Fano...The optical properties of cylindrical core–shell nanorods(CCSNs)are theoretically investigated in this paper.The results show that Fano resonance can be generated in CCSNs,and the wavelength and the intensity at Fano dip can be tuned respectively by adjusting the field coupling of cavity mode inside and near field on gold surface.The high tuning sensitivity which is about 400 nm per refractive-index unit can be obtained,and an easy-to-realize tunable parameter is also proposed.A two-oscillator model is also introduced to describe the generation of Fano resonance in CCSNs,and the results from this model are in good agreement with theoretical results.The CCSNs investigated in this work may have promising applications in optical devices.展开更多
A composite ceramic with nominal composition of 45.0 wt%（Ba0.5Sr0.5）TiO3–55.0 wt%MgO（acronym is BST–MgO） is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined ...A composite ceramic with nominal composition of 45.0 wt%（Ba0.5Sr0.5）TiO3–55.0 wt%MgO（acronym is BST–MgO） is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined BST–Mg O composite ceramic exhibits good microwave dielectric properties at X-band with appropriate dielectric constant εr around85, lower dielectric loss tan δ about 0.01, and higher permittivity tunability 14.8% at 8.33 k V/cm. An ultrahigh E-field tunability of working frequency up to 11.0%（i.e., from 9.1 GHz to 10.1 GHz with a large frequency shift of 1000 MHz）at a DC bias field from 0 to 8.33 k V/cm and a considerably large center gain over 7.5 d B are obtained in the designed frequency reconfigurable microstrip antenna. These results demonstrate that BST materials are promising for the frequency reconfigurable antenna.展开更多
The electric-field tunability of dielectric constant （ε-E） in Sr1-xMnxTiO3 films （x = 0, 0.005, 0.010, 0.020 and 0.030） prepared by the metal organic decomposition method on Pt/Ti/SiO2/Si substrates is studied in...The electric-field tunability of dielectric constant （ε-E） in Sr1-xMnxTiO3 films （x = 0, 0.005, 0.010, 0.020 and 0.030） prepared by the metal organic decomposition method on Pt/Ti/SiO2/Si substrates is studied in the frequency range from 100Hz to 1MHz with different Mn contents at different temperatures. The frequencyindependent tunability increases strongly with decreasing the temperature from 300 K to 150K. The tunability （-31%） in thin films （x = 0.005） at 150K is obtained and the temperature for the same tunability in ceramics is about 60 K lower than the present one. This tunability is comparable with that in one of ferroelectric Sr1-1.sxBixTiO3 thin films. Similarly, the well-defined P（E） hysteresis 10013 and 2Pr （1.2 μC/cm^2） can be obtained at 300 K in Sr1-xMnxTiO3 films with z = 0.005. Both the existence of electric dipole or poled micro domain introduced by the doped Mn2＋ located in the off-center position at Sr sites and the strain between the thin film and the substrate are the origins of the tunable and polar behavior in Sr1-xMnxTiO3 films.展开更多
It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(...It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(YPrIG)ex-hibits the merits of high saturation magnetization and a much high resistivity,which are helpful for realizing magnetoelectric double tuning and suppressing the dielectric loss of BST film.In this work,Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)(YPrIG/BST)composite films were fabricated by sol-gel method.The com-posite films exhibited a low dielectric loss(0.0087),and got a magnetic tunability of 11.73%at 10 kOe and 1.44 MHz.Compared with BST film,the tunability of YPrIG/BST film was enhanced from 56.25%to 73.24%under the bias electric field of 800 kV/cm.Additionally,YPrIG/BST films exhibited an electromag-netic double adjustability.The electromagnetic tunability of YPrIG/BST composite films was as high as 80.40%at 1.44 MHz,under the DC bias electric field of 800 kV/cm and magnetic field of 10 kOe.This phenomenon can be explained in terms of the superposition effect of electric field and magnetic field.展开更多
We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses a...We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.展开更多
Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs ...Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs has been controlled by tuning the oleic acid(OA)/oleylamine(OLA)feed ratio in conventional injection-based synthesis.Although the emerging bimolecular nucleophilic substitution(S_(N)2)-based heatup synthesis enables the production of high-quality and monodisperse PNCs,achieving dimensional tunability by altering the OA/OLA feed ratio remains challenging in this approach.Herein,we present an integrated strategy for controlling the dimensionality and surface properties of CsPbI_(3)-PNCs based on the S_(N)2-based heat-up method.Our approach focuses on the regulation of OLA protonation and oleylammonium(OAM^(+))latticeforming behavior.Using chemical analysis,we identify the protonation routes of OLA in S_(N)2 reactions and demonstrate that adjusting the acid–base and S_(N)2 reactions involving OA and OLA can reduce OLA protonation and the subsequent formation of OAM^(+).Furthermore,by enhancing the competitive lattice-forming behavior of Cs^(+)over OAM+,we suppress excessive surface termination by OAM^(+).These approaches achieve dimensional tunability between two-dimensional(2D)nanoplatelets and three-dimensional(3D)nanocubes in the S_(N)2-based heat-up synthesis,along with subsequent spectral control of optical features.To independently optimize their surface passivation,we employ a post-synthetic passivation(PSP)strategy using OAM^(+)–I−pairs,which increases the photoluminescence quantum yield of PNCs from 71.9%to 81.7%by reducing surface defects.展开更多
Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)thin film heterostructure was claimed by Jiao et al.in Journal of Materials Science&Technology 202(2024)174 as a tunable dielectric material with superior perfo...Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)thin film heterostructure was claimed by Jiao et al.in Journal of Materials Science&Technology 202(2024)174 as a tunable dielectric material with superior performance achieved under simultaneous application of the electric and magnetic fields at a particular frequency of 1.44 MHz.However,here we express concerns regarding the real presence of the phenomenon at 1.44 MHz in the studied structures based on the literature and dielectric spectroscopy principles.We also note that the presented dielectric results and their interpretations are contradictory.展开更多
Integration of graphene in silicon-based micro-/nanoelectromechanical systems(MEMS/NEMS)marries the robustness of silicon-based materials with the exceptional physical properties of graphene,drastically enhancing the ...Integration of graphene in silicon-based micro-/nanoelectromechanical systems(MEMS/NEMS)marries the robustness of silicon-based materials with the exceptional physical properties of graphene,drastically enhancing the system’s regulation performance which now is key for many advanced applications in nanotechnology.Here,we experimentally demonstrate and theoretically analyze a powerful on-chip integration principle consisting of a hybrid graphene/silicon nitride membrane with metallic leads on top that enables an extremely large static and dynamic parameter regulation.When a static voltage is applied to the leads of the integrated structure,a spatially confined localized electrothermomechanical(ETM)effect results in ultra-wide frequency tuning,deformation(buckling transition)and regulation of the mechanical properties.Moreover,by injecting an alternating voltage to the leads,we can excite the resonator vibrating even far beyond its linear regime without a complex and space consuming actuation system.Our results prove that the scheme provides a compact integrated system possessing mechanical robustness,high controllability,and fast response.It not only expands the limit of the application range of MEMS/NEMS devices,but also enables the further miniaturization of the device.展开更多
We suggest a low cross-talk plasmonic cross-connector based on a metal/insulator/metal cavity and waveguides.We separately investigate the isolated cavity mode, the waveguide mode, and the combination of cavity and wa...We suggest a low cross-talk plasmonic cross-connector based on a metal/insulator/metal cavity and waveguides.We separately investigate the isolated cavity mode, the waveguide mode, and the combination of cavity and waveguide modes using a finite-different time-domain method. Due to resonant tunneling and the cutoff frequency of the odd waveguide mode, our proposed structure achieves a high throughput transmission ratio and eliminates cross-talk. Furthermore, the proposed structure has a broadband tunability of 587 nm, which can be achieved by modulating the cavity air gap thickness. This structure enables the miniaturization of photonic integrated circuits and sensing applications.展开更多
MXene-based films have been intensively explored for construction of piezoresistive flexible pressure sensors owing to their excellent mechanical and electrical properties.High pressure sensitivity relies on pre-moldi...MXene-based films have been intensively explored for construction of piezoresistive flexible pressure sensors owing to their excellent mechanical and electrical properties.High pressure sensitivity relies on pre-molding a flexible substrate,or regulating the micromorphology of MXene sheets,to obtain a micro-structured surface.However,the two avenues usually require complicated and time-consuming microfabrication or wet chemical processing,and are limited to non-adjustable topographicelectrical(topo-electro)properties.Herein,we propose a lithographic printing inspired in-situ transfer(LIPIT)strategy to fabricate MXene-ink films(MIFs).In LIPIT,MIFs not only inherit ridge-and-valley microstructure from paper substrate,but also achieve localized topo-electro tunability by programming ink-writing patterns and cycles.The MIF-based flexible pressure sensor with periodical topo-electro gradient exhibits remarkably boosted sensitivity in a wide sensing range(low detection limit of 0.29 Pa and working range of 100 kPa).The MIF sensor demonstrates versatile applicability in both subtle and vigorous pressuresensing fields,ranging from pulse wave extraction and machine learning-assisted surface texture recognition to piano-training glove(PT-glove)for piano learning.The LIPIT is quick,low-cost,and compatible with free ink/substrate combinations,which promises a versatile toolbox for designing functional MXene films with tailored morphological-mechanical-electrical properties for extended application scenarios.展开更多
All-inorganic zero-dimensional(0D)tetrahedrite(Cu12Sb4S13,CAS)quantum dots(QDs)have attracted extensive attention due to their excellent optical properties,bandgap tunability,and carrier mobility.In this paper,various...All-inorganic zero-dimensional(0D)tetrahedrite(Cu12Sb4S13,CAS)quantum dots(QDs)have attracted extensive attention due to their excellent optical properties,bandgap tunability,and carrier mobility.In this paper,various sized CAS QDs(5.1,6.7,and 7.9 nm)are applied as a switching layer with the structure F:Sn O2(FTO)/CAS QDs/Au,and in doing so,the nonvolatile resistive-switching behavior of electronics based on CAS QDs is reported.The SET/RESET voltage tunability with size dependency is observed for memory devices based on CAS QDs for the first time.Results suggest that differently sized CAS QDs result in different band structures and the regulation of the SET/RESET voltage occurs simply and effectively due to the uniform size of the CAS QDs.Moreover,the presented memory devices have reliable bipolar resistive-switching properties,a resistance(ON/OFF)ratio larger than 104,high reproducibility,and good data retention ability.After 1.4×10^6s of stability testing and 104cycles of quick read tests,the change rate of the ON/OFF ratio is smaller than 0.1%.Furthermore,resistiveswitching stability can be improved by ensuring a uniform particle size for the CAS QDs.The theoretical calculations suggest that the space-charge-limited currents(SCLCs),which are functioned by Cu 3d,Cu 3p and S 3p to act as electron selftrapping centers due to their quantum confinement and form conduction pathways under an electric field,are responsible for the resistive-switching effect.This paper demonstrates that CAS QDs are promising as a novel resistive-switching material in memory devices and can be used to facilitate the application of next-generation nonvolatile memory.展开更多
The luminescence modulation behaviour under the in-situ electric field of rare-earth doped KSr_(2)Nb_(5)O_(15) ceramics opened a new door for the development of dielectric materials.Where the understanding the effect ...The luminescence modulation behaviour under the in-situ electric field of rare-earth doped KSr_(2)Nb_(5)O_(15) ceramics opened a new door for the development of dielectric materials.Where the understanding the effect of rare-earth doping on the electric properties of host,especially at the similar doping concentration with luminescence researches(low concentrations)is very important for the exploration of mechanism of electric-luminescent coupling effect.In this work,Nd^(3+)-doped KSr_(2)Nb_(5)O_(15)(KSN-xNd)ceramics were synthesized,and the electric properties were investigated systematically.Our results suggest that the Nd^(3+) doping slightly increased the phase transition temperatures and improved the piezoelectric response of KSr_(2)Nb_(5)O_(15).Most importantly,a bidirectional dielectric tunability is revealed in KSr_(2)Nb_(5)O_(15).The dielectric permittivity can be adjusted by the DC electric bias,with tunability ranging from12.3% to 21.9%.The related mechanism and relationship between the bidirectional dielectric tunability and ferroelectricity are revealed by temperature-dependent dielectric and ferroelectric characterization.The researches of electric properties and bidirectional dielectric tunability of KSN-based ceramics paved the way to further exploration of electric-luminescent coupling mechanism.展开更多
Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen ba...Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.展开更多
A simple configuration dual-wavelength fiber laser,by combining the first-order Brillouin laser and the residual pump laser,is proposed and experimentally demonstrated.A 1 km long single-mode fiber is used as the stim...A simple configuration dual-wavelength fiber laser,by combining the first-order Brillouin laser and the residual pump laser,is proposed and experimentally demonstrated.A 1 km long single-mode fiber is used as the stimulated Brillouin scattering gain medium pumped by a narrow linewidth tunable laser source（TLS）.Through simply adjusting the TLS output power,power-equalized dual-wavelength lasing can be achieved with a high optical signal to noise ratio（OSNR） of 〉80 d B.With the good tunability of the TLS,the dual-wavelength fiber laser has a tunable range of -130 nm,and simultaneously the beat frequency of the two lasing wavelengths can be tuned from 10.1875 to 11.0815 GHz with the tunable range of 0.8940 GHz.The high stability of the dualwavelength operation is experimentally verified by the measured beat frequency fluctuation of ≤6 MHz in 1 h and power fluctuation of ≤0.03 d B in 2 h.The temporal characteristics of the fiber laser are also investigated experimentally.The fiber laser will find good applications in fiber sensing and microwave photonics areas.展开更多
Two-dimensional(2D)organic-inorganic hybrid perovskites(OIHPs)have attracted phenomenal attention because of their superior optoelectronic performances.The combination of their structural tunability and material stabi...Two-dimensional(2D)organic-inorganic hybrid perovskites(OIHPs)have attracted phenomenal attention because of their superior optoelectronic performances.The combination of their structural tunability and material stability offers an unprecedented opportunity to engineer materials with unique functionalities.However,developing a rapid and effective design method for introducing luminescence into dielectric switch and realizing controllable regulation has been an enormous challenge.Thus far,materials with tunable optoelectronic multichannel response have not been successfully implemented.In this study,we successfully developed a facile and effective mechanochemical method for realizing the integration and regulation of luminescence and dielectric switch in 2D perovskites,which is unprecedented for the design of dielectric switching materials.The mild external mechanical stimuli enabled the formation of Mn ion-doped 2D hybrid perovskites(Cyclopropylammonium)2Pb1-xMnxBr4 with excellent dielectric switch and rapidly controllable luminescence of highly efficient blue light,white light,pink light,and orange light.This work will provide a new perspective on the rapid and effective design of multifunctional materials and can inspire the future development of low-cost and high-efficiency electronics.展开更多
Photonic generation of radio-frequency（RF） arbitrary microwave waveform with ultra-wide frequency tunable range based on a dispersion compensated optoelectronic oscillator（OEO） is proposed and experimentally demon...Photonic generation of radio-frequency（RF） arbitrary microwave waveform with ultra-wide frequency tunable range based on a dispersion compensated optoelectronic oscillator（OEO） is proposed and experimentally demonstrated. Dispersion compensation scheme and specially designed fiber Bragg grating（FBG）-based Fabry-Perot（F-P） filters are employed in the OEO loop to realize a frequency tunable range of 3.5-45.4 GHz. An optimization process provided by the combination of an erbium-doped fiber amplifier（EDFA）and FBG is employed to improve the signal-to-noise ratio（SNR） of final RF signals. The generation of linearfrequency and phase-coded microwave waveforms, with a tunable carrier frequency ranging from 4 to 45 GHz and tuned chirping bandwidths or code rates, is experimentally demonstrated.展开更多
We present a compact optical delay line(ODL)with wide-range continuous tunability on thin-film lithium niobate platform.The proposed device integrates an unbalanced Mach-Zehnder interferometer(MZI)architecture with du...We present a compact optical delay line(ODL)with wide-range continuous tunability on thin-film lithium niobate platform.The proposed device integrates an unbalanced Mach-Zehnder interferometer(MZI)architecture with dual tunable couplers,where each coupler comprises two 2×2 multimode interferometers and a MZI phase-tuning section.Experimental results demonstrate continuous delay tuning from 0 to 293 ps through synchronized control of coupling coefficients,corresponding to a 4 cm path difference between interferometer arms.The measured delay range exhibits excellent agreement with theoretical predictions derived from ODL waveguide parameters.This result addresses critical challenges in integrated photonic systems that require precise temporal control,particularly for applications in optical communications and quantum information processing,where a wide tuning range is paramount.展开更多
Eutectogels are considered to have immense application potential in the field of flexible wearable ionotronic devices because of their excellent ionic conductivity,thermal and electrochemical stability,and non-volatil...Eutectogels are considered to have immense application potential in the field of flexible wearable ionotronic devices because of their excellent ionic conductivity,thermal and electrochemical stability,and non-volatility.However,most existing technologies still struggle to achieve synergistic optimization of key performance indicators,such as high mechanical strength and ionic conductivity.To address this chal-lenge,this study successfully prepared a green eutectogel material with outstanding comprehensive properties by leveraging the high solubility of glycerol in a polymerizable deep eutectic solvent(DES)composed of acrylic acid and choline chloride.The resulting eutectogels exhibited a high transparency(89%),high mechanical strength(up to 2.8 MPa),and exceptional tensile performance(up to 1385%).The fabricated flexible sensor demonstrated ideal linear sensitivity(gauge factor:0.88),a broad response range(1%-100%),and reliable stability(over 1000 cycles),en-abling the precise monitoring of human motion(e.g.,finger bending and wrist rotation).The flexible strain sensor based on this eutectogel is ex-pected to show promising prospects for medical monitoring,human-machine interaction,and industrial sensing applications.展开更多
The demand for lightweight and multifunctional surface structure in high-end equipment is steadily growing.The harmonization between flexibility and electromagnetic tunability has become a significant subject for stea...The demand for lightweight and multifunctional surface structure in high-end equipment is steadily growing.The harmonization between flexibility and electromagnetic tunability has become a significant subject for stealth morphing aircraft.This paper presents a microwave absorbing structure based on the kirigami configuration,aiming at improving the conformality with the negative Poisson’s ratio characteristic and expanding the radar stealth range with tunability.A precise electromagnetic reflectivity model of the impedance surface was established by the inversion method,and an integrated optimization algorithm was employed to optimize the structural parameters based on numerical analysis.Specimens composed of thermoplastic polyurethane elastic colloids and resistive materials were prepared to assess the in-plane mechanical tensile and electromagnetic absorption performances through experimental methods.The results indicate that the original absorption band spans 6.2-11.1 GHz,shifts to 8-18 GHz with stretching at a panel rotation angle of 16°,and remains nearly constant for further stretching.The specimens adhere to complex curved surfaces well in experiments and maintain the electromagnetic absorption performance compared with flat surfaces.This research offers a valuable reference for designing electromagnetic stealth structures that are highly stretchable and adjustable.展开更多
基金Project supported by the National Basic Research Program of China(Grant Nos.2015CB755403 and 2014CB339802)the National Key Research and Development Program of China(Grant No.2016YFC0101001)+2 种基金the National Natural Science Foundation of China(Grant Nos.61775160,61771332,and 61471257)China Postdoctoral Science Foundation(Grant No.2016M602954)Postdoctoral Science Foundation of Chongqing,China(Grant No.Xm2016021)
文摘A wide terahertz tuning range from 0.96 THz to 7.01 THz has been demonstrated based on ring-cavity THz wave parametric oscillator with a KTiOPO_(4)(KTP)crystal.The tuning range was observed intermittently from 0.96 THz to 1.87 THz,from 3.04 THz to 3.33 THz,from 4.17 THz to 4.48 THz,from 4.78 THz to 4.97 THz,from 5.125 THz to 5.168 THz,from5.44 THz to 5.97 THz,and from 6.74 THz to 7.01 THz.The dual-Stokes wavelengths resonance phenomena were observed in some certain tuning angle ranges.Through the theoretical analysis of the dispersion curve of the KTP crystal,the intermittent THz wave tuning range and dual-wavelength Stokes waves operation during angle tuning process were explained.The theoretical analysis was in good agreement with the experiment results.The maximum THz output voltage detected by Golay cell was 1.7 V at 5.7 THz under the pump energy of 210 mJ,corresponding to the THz wave output energy of5.47μJ and conversion efficiency of 2.6×10^(-5).
基金Project supported by the National Natural Science Foundation of China(Grant No.11647021)。
文摘The optical properties of cylindrical core–shell nanorods(CCSNs)are theoretically investigated in this paper.The results show that Fano resonance can be generated in CCSNs,and the wavelength and the intensity at Fano dip can be tuned respectively by adjusting the field coupling of cavity mode inside and near field on gold surface.The high tuning sensitivity which is about 400 nm per refractive-index unit can be obtained,and an easy-to-realize tunable parameter is also proposed.A two-oscillator model is also introduced to describe the generation of Fano resonance in CCSNs,and the results from this model are in good agreement with theoretical results.The CCSNs investigated in this work may have promising applications in optical devices.
基金Project supported by the National Natural Science Foundation of China(Grant No.11074040)the Key Project of Shandong Provincial Department of Science and TechnologyChina(Grant No.ZR2012FZ006)
文摘A composite ceramic with nominal composition of 45.0 wt%（Ba0.5Sr0.5）TiO3–55.0 wt%MgO（acronym is BST–MgO） is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined BST–Mg O composite ceramic exhibits good microwave dielectric properties at X-band with appropriate dielectric constant εr around85, lower dielectric loss tan δ about 0.01, and higher permittivity tunability 14.8% at 8.33 k V/cm. An ultrahigh E-field tunability of working frequency up to 11.0%（i.e., from 9.1 GHz to 10.1 GHz with a large frequency shift of 1000 MHz）at a DC bias field from 0 to 8.33 k V/cm and a considerably large center gain over 7.5 d B are obtained in the designed frequency reconfigurable microstrip antenna. These results demonstrate that BST materials are promising for the frequency reconfigurable antenna.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51225201,61271078,and 51102133the National Basic Research Program of China under Grant No 2015CB921201+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities
文摘The electric-field tunability of dielectric constant （ε-E） in Sr1-xMnxTiO3 films （x = 0, 0.005, 0.010, 0.020 and 0.030） prepared by the metal organic decomposition method on Pt/Ti/SiO2/Si substrates is studied in the frequency range from 100Hz to 1MHz with different Mn contents at different temperatures. The frequencyindependent tunability increases strongly with decreasing the temperature from 300 K to 150K. The tunability （-31%） in thin films （x = 0.005） at 150K is obtained and the temperature for the same tunability in ceramics is about 60 K lower than the present one. This tunability is comparable with that in one of ferroelectric Sr1-1.sxBixTiO3 thin films. Similarly, the well-defined P（E） hysteresis 10013 and 2Pr （1.2 μC/cm^2） can be obtained at 300 K in Sr1-xMnxTiO3 films with z = 0.005. Both the existence of electric dipole or poled micro domain introduced by the doped Mn2＋ located in the off-center position at Sr sites and the strain between the thin film and the substrate are the origins of the tunable and polar behavior in Sr1-xMnxTiO3 films.
基金supported by the National Natural Science Foundation of China(Nos.52171191,52371198)Shaanxi Key Program for International Science and Technology Coopera-tion Projects(No.2021KWZ-12)the Youth Innovation Team of Shaanxi Universities.
文摘It is hard to simultaneously realize the high dielectric tunability and low loss for the single Ba_(0.6)Sr_(0.4)TiO_(3)(BST)dielectric film made through chemical method.Garnet structured Y_(2.80)Pr_(0.20)Fe_(5)O_(12)(YPrIG)ex-hibits the merits of high saturation magnetization and a much high resistivity,which are helpful for realizing magnetoelectric double tuning and suppressing the dielectric loss of BST film.In this work,Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)(YPrIG/BST)composite films were fabricated by sol-gel method.The com-posite films exhibited a low dielectric loss(0.0087),and got a magnetic tunability of 11.73%at 10 kOe and 1.44 MHz.Compared with BST film,the tunability of YPrIG/BST film was enhanced from 56.25%to 73.24%under the bias electric field of 800 kV/cm.Additionally,YPrIG/BST films exhibited an electromag-netic double adjustability.The electromagnetic tunability of YPrIG/BST composite films was as high as 80.40%at 1.44 MHz,under the DC bias electric field of 800 kV/cm and magnetic field of 10 kOe.This phenomenon can be explained in terms of the superposition effect of electric field and magnetic field.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFB0402105)
文摘We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.
基金supported by the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(Nos.RS-2023-00207907 and RS-2024-00444458).
文摘Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs has been controlled by tuning the oleic acid(OA)/oleylamine(OLA)feed ratio in conventional injection-based synthesis.Although the emerging bimolecular nucleophilic substitution(S_(N)2)-based heatup synthesis enables the production of high-quality and monodisperse PNCs,achieving dimensional tunability by altering the OA/OLA feed ratio remains challenging in this approach.Herein,we present an integrated strategy for controlling the dimensionality and surface properties of CsPbI_(3)-PNCs based on the S_(N)2-based heat-up method.Our approach focuses on the regulation of OLA protonation and oleylammonium(OAM^(+))latticeforming behavior.Using chemical analysis,we identify the protonation routes of OLA in S_(N)2 reactions and demonstrate that adjusting the acid–base and S_(N)2 reactions involving OA and OLA can reduce OLA protonation and the subsequent formation of OAM^(+).Furthermore,by enhancing the competitive lattice-forming behavior of Cs^(+)over OAM+,we suppress excessive surface termination by OAM^(+).These approaches achieve dimensional tunability between two-dimensional(2D)nanoplatelets and three-dimensional(3D)nanocubes in the S_(N)2-based heat-up synthesis,along with subsequent spectral control of optical features.To independently optimize their surface passivation,we employ a post-synthetic passivation(PSP)strategy using OAM^(+)–I−pairs,which increases the photoluminescence quantum yield of PNCs from 71.9%to 81.7%by reducing surface defects.
基金the FCT/MEC(PIDDAC)within FCT independent researcher grant 2021.02284.CEECIND/CP1659/CT0018(DOI 10.54499/2021.02284.CEECIND/CP1659/CT0018)+1 种基金supported by national funds,through FCT in the scope of the framework contract foreseen in numbers 4,5,and 6 of article 23 of the Decree Law 57/2016,of 29 August,UIDB/00481/2020 and UIDP/00481/2020,DOI 10.54499/UIDB/00481/2020 and DOI 10.54499/UIDP/00481/2020CENTRO-01-0145-FEDER-022083-Centro Portugal Regional Operational Programme(Centro2020),under the PORTUGAL 2020 Partnership Agreement,through the European Regional Develop-ment Fund.
文摘Y_(2.80)Pr_(0.20)Fe_(5)O_(12)/Ba_(0.6)Sr_(0.4)TiO_(3)thin film heterostructure was claimed by Jiao et al.in Journal of Materials Science&Technology 202(2024)174 as a tunable dielectric material with superior performance achieved under simultaneous application of the electric and magnetic fields at a particular frequency of 1.44 MHz.However,here we express concerns regarding the real presence of the phenomenon at 1.44 MHz in the studied structures based on the literature and dielectric spectroscopy principles.We also note that the presented dielectric results and their interpretations are contradictory.
基金financial support from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)through Project-ID 425217212(SFB 1432)and project 510766045the major program in digital intelligence,Shapingba,Chongqing(Grant No.20240204)the Wisconsin Alumni Research Foundation(WARF)via the Accelerator Program.
文摘Integration of graphene in silicon-based micro-/nanoelectromechanical systems(MEMS/NEMS)marries the robustness of silicon-based materials with the exceptional physical properties of graphene,drastically enhancing the system’s regulation performance which now is key for many advanced applications in nanotechnology.Here,we experimentally demonstrate and theoretically analyze a powerful on-chip integration principle consisting of a hybrid graphene/silicon nitride membrane with metallic leads on top that enables an extremely large static and dynamic parameter regulation.When a static voltage is applied to the leads of the integrated structure,a spatially confined localized electrothermomechanical(ETM)effect results in ultra-wide frequency tuning,deformation(buckling transition)and regulation of the mechanical properties.Moreover,by injecting an alternating voltage to the leads,we can excite the resonator vibrating even far beyond its linear regime without a complex and space consuming actuation system.Our results prove that the scheme provides a compact integrated system possessing mechanical robustness,high controllability,and fast response.It not only expands the limit of the application range of MEMS/NEMS devices,but also enables the further miniaturization of the device.
基金National Research Foundation of Korea(NRF)(NRF-2015R1A2A1A15055998,NRF-2013M3C1A3065051,NRF-2016R1C1B2007007)
文摘We suggest a low cross-talk plasmonic cross-connector based on a metal/insulator/metal cavity and waveguides.We separately investigate the isolated cavity mode, the waveguide mode, and the combination of cavity and waveguide modes using a finite-different time-domain method. Due to resonant tunneling and the cutoff frequency of the odd waveguide mode, our proposed structure achieves a high throughput transmission ratio and eliminates cross-talk. Furthermore, the proposed structure has a broadband tunability of 587 nm, which can be achieved by modulating the cavity air gap thickness. This structure enables the miniaturization of photonic integrated circuits and sensing applications.
基金supported by the National Natural Science Foundation of China(Nos.62122080,62261136551,and 52203365)the Natural Science Foundation of Shanghai(Nos.22ZR1481700 and 22dz1205000)the Shanghai Pujiang Program(No.21PJ1414800).
文摘MXene-based films have been intensively explored for construction of piezoresistive flexible pressure sensors owing to their excellent mechanical and electrical properties.High pressure sensitivity relies on pre-molding a flexible substrate,or regulating the micromorphology of MXene sheets,to obtain a micro-structured surface.However,the two avenues usually require complicated and time-consuming microfabrication or wet chemical processing,and are limited to non-adjustable topographicelectrical(topo-electro)properties.Herein,we propose a lithographic printing inspired in-situ transfer(LIPIT)strategy to fabricate MXene-ink films(MIFs).In LIPIT,MIFs not only inherit ridge-and-valley microstructure from paper substrate,but also achieve localized topo-electro tunability by programming ink-writing patterns and cycles.The MIF-based flexible pressure sensor with periodical topo-electro gradient exhibits remarkably boosted sensitivity in a wide sensing range(low detection limit of 0.29 Pa and working range of 100 kPa).The MIF sensor demonstrates versatile applicability in both subtle and vigorous pressuresensing fields,ranging from pulse wave extraction and machine learning-assisted surface texture recognition to piano-training glove(PT-glove)for piano learning.The LIPIT is quick,low-cost,and compatible with free ink/substrate combinations,which promises a versatile toolbox for designing functional MXene films with tailored morphological-mechanical-electrical properties for extended application scenarios.
基金supported by the National Natural Science Foundation of China(51572205,11674258 and 51802093)the Joint Fund of Ministry of Education for Equipment Pre-research the Fundamental Research(6141A02022262)+1 种基金the Excellent Dissertation Cultivation Funds of Wuhan University of Technology(2018-YS-001)the Fundamental Research Funds for the Central Universities(2019zy-007)。
文摘All-inorganic zero-dimensional(0D)tetrahedrite(Cu12Sb4S13,CAS)quantum dots(QDs)have attracted extensive attention due to their excellent optical properties,bandgap tunability,and carrier mobility.In this paper,various sized CAS QDs(5.1,6.7,and 7.9 nm)are applied as a switching layer with the structure F:Sn O2(FTO)/CAS QDs/Au,and in doing so,the nonvolatile resistive-switching behavior of electronics based on CAS QDs is reported.The SET/RESET voltage tunability with size dependency is observed for memory devices based on CAS QDs for the first time.Results suggest that differently sized CAS QDs result in different band structures and the regulation of the SET/RESET voltage occurs simply and effectively due to the uniform size of the CAS QDs.Moreover,the presented memory devices have reliable bipolar resistive-switching properties,a resistance(ON/OFF)ratio larger than 104,high reproducibility,and good data retention ability.After 1.4×10^6s of stability testing and 104cycles of quick read tests,the change rate of the ON/OFF ratio is smaller than 0.1%.Furthermore,resistiveswitching stability can be improved by ensuring a uniform particle size for the CAS QDs.The theoretical calculations suggest that the space-charge-limited currents(SCLCs),which are functioned by Cu 3d,Cu 3p and S 3p to act as electron selftrapping centers due to their quantum confinement and form conduction pathways under an electric field,are responsible for the resistive-switching effect.This paper demonstrates that CAS QDs are promising as a novel resistive-switching material in memory devices and can be used to facilitate the application of next-generation nonvolatile memory.
基金This work was supported by the China-Poland International Collaboration Fund of National Natural Science Foundation of China(No.51961135301)National Natural Science Foundation of China(No.51702259)+2 种基金the National Key R&D Foundation of the Ministry of Science and Technology(No.2018YFB1107405)the Basic Research Program of Shenzhen(No.JCYJ20170306155944271)the Fundamental Research Funds for the Central Universities(No.06450-G2019KY0601,3102019MS0406).
文摘The luminescence modulation behaviour under the in-situ electric field of rare-earth doped KSr_(2)Nb_(5)O_(15) ceramics opened a new door for the development of dielectric materials.Where the understanding the effect of rare-earth doping on the electric properties of host,especially at the similar doping concentration with luminescence researches(low concentrations)is very important for the exploration of mechanism of electric-luminescent coupling effect.In this work,Nd^(3+)-doped KSr_(2)Nb_(5)O_(15)(KSN-xNd)ceramics were synthesized,and the electric properties were investigated systematically.Our results suggest that the Nd^(3+) doping slightly increased the phase transition temperatures and improved the piezoelectric response of KSr_(2)Nb_(5)O_(15).Most importantly,a bidirectional dielectric tunability is revealed in KSr_(2)Nb_(5)O_(15).The dielectric permittivity can be adjusted by the DC electric bias,with tunability ranging from12.3% to 21.9%.The related mechanism and relationship between the bidirectional dielectric tunability and ferroelectricity are revealed by temperature-dependent dielectric and ferroelectric characterization.The researches of electric properties and bidirectional dielectric tunability of KSN-based ceramics paved the way to further exploration of electric-luminescent coupling mechanism.
基金financially supported by the National Natural Science Foundation of China(U21A20311,U24A2040,52171141,52272117)the Natural Science Foundation of Shandong Province(ZR2022JQ19)+3 种基金the Key Technology Research Project of Shandong Province(2023CXGC010202)the Taishan Industrial Experts Program(TSCX202306142)the Core Facility Sharing Platform of Shandong Universitythe Foundation of Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University。
文摘Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.
基金supported by the Natural Science Foundation of Hebei Province(No.F2016201023)the Technology Foundation for Selected Overseas Chinese Scholar of MOHRSS(No.CG2015003006)+1 种基金the Advanced Talents Program of Hebei Educational Committee(No.GCC2014020)the International Science and Technology Cooperation Program of China(No.2014DFA12930)
文摘A simple configuration dual-wavelength fiber laser,by combining the first-order Brillouin laser and the residual pump laser,is proposed and experimentally demonstrated.A 1 km long single-mode fiber is used as the stimulated Brillouin scattering gain medium pumped by a narrow linewidth tunable laser source（TLS）.Through simply adjusting the TLS output power,power-equalized dual-wavelength lasing can be achieved with a high optical signal to noise ratio（OSNR） of 〉80 d B.With the good tunability of the TLS,the dual-wavelength fiber laser has a tunable range of -130 nm,and simultaneously the beat frequency of the two lasing wavelengths can be tuned from 10.1875 to 11.0815 GHz with the tunable range of 0.8940 GHz.The high stability of the dualwavelength operation is experimentally verified by the measured beat frequency fluctuation of ≤6 MHz in 1 h and power fluctuation of ≤0.03 d B in 2 h.The temporal characteristics of the fiber laser are also investigated experimentally.The fiber laser will find good applications in fiber sensing and microwave photonics areas.
基金the National Natural Science Foundation of China(21991141)the Natural Science Foundation of Zhejiang Province(LZ20B010001)Zhejiang Normal University。
文摘Two-dimensional(2D)organic-inorganic hybrid perovskites(OIHPs)have attracted phenomenal attention because of their superior optoelectronic performances.The combination of their structural tunability and material stability offers an unprecedented opportunity to engineer materials with unique functionalities.However,developing a rapid and effective design method for introducing luminescence into dielectric switch and realizing controllable regulation has been an enormous challenge.Thus far,materials with tunable optoelectronic multichannel response have not been successfully implemented.In this study,we successfully developed a facile and effective mechanochemical method for realizing the integration and regulation of luminescence and dielectric switch in 2D perovskites,which is unprecedented for the design of dielectric switching materials.The mild external mechanical stimuli enabled the formation of Mn ion-doped 2D hybrid perovskites(Cyclopropylammonium)2Pb1-xMnxBr4 with excellent dielectric switch and rapidly controllable luminescence of highly efficient blue light,white light,pink light,and orange light.This work will provide a new perspective on the rapid and effective design of multifunctional materials and can inspire the future development of low-cost and high-efficiency electronics.
文摘Photonic generation of radio-frequency（RF） arbitrary microwave waveform with ultra-wide frequency tunable range based on a dispersion compensated optoelectronic oscillator（OEO） is proposed and experimentally demonstrated. Dispersion compensation scheme and specially designed fiber Bragg grating（FBG）-based Fabry-Perot（F-P） filters are employed in the OEO loop to realize a frequency tunable range of 3.5-45.4 GHz. An optimization process provided by the combination of an erbium-doped fiber amplifier（EDFA）and FBG is employed to improve the signal-to-noise ratio（SNR） of final RF signals. The generation of linearfrequency and phase-coded microwave waveforms, with a tunable carrier frequency ranging from 4 to 45 GHz and tuned chirping bandwidths or code rates, is experimentally demonstrated.
基金supported by the National Natural Science Foundation of China(Grant Nos.12192251,12334014,12404378,92480001,12134001,12174113,12174107,12474325,12404379,and 12474378)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301403)+1 种基金Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Fundamental Research Funds for the Central Universities,the Engineering Research Center for Nanophotonics&Advanced Instrument,Ministry of Education,East China Normal University(Grant No.2023nmc005).
文摘We present a compact optical delay line(ODL)with wide-range continuous tunability on thin-film lithium niobate platform.The proposed device integrates an unbalanced Mach-Zehnder interferometer(MZI)architecture with dual tunable couplers,where each coupler comprises two 2×2 multimode interferometers and a MZI phase-tuning section.Experimental results demonstrate continuous delay tuning from 0 to 293 ps through synchronized control of coupling coefficients,corresponding to a 4 cm path difference between interferometer arms.The measured delay range exhibits excellent agreement with theoretical predictions derived from ODL waveguide parameters.This result addresses critical challenges in integrated photonic systems that require precise temporal control,particularly for applications in optical communications and quantum information processing,where a wide tuning range is paramount.
基金supported by the National Natural Science Foundation of China(Nos.22301037, 22401045)the Natural Science Foundation of Guangdong Province(No.2022A1515110867).
文摘Eutectogels are considered to have immense application potential in the field of flexible wearable ionotronic devices because of their excellent ionic conductivity,thermal and electrochemical stability,and non-volatility.However,most existing technologies still struggle to achieve synergistic optimization of key performance indicators,such as high mechanical strength and ionic conductivity.To address this chal-lenge,this study successfully prepared a green eutectogel material with outstanding comprehensive properties by leveraging the high solubility of glycerol in a polymerizable deep eutectic solvent(DES)composed of acrylic acid and choline chloride.The resulting eutectogels exhibited a high transparency(89%),high mechanical strength(up to 2.8 MPa),and exceptional tensile performance(up to 1385%).The fabricated flexible sensor demonstrated ideal linear sensitivity(gauge factor:0.88),a broad response range(1%-100%),and reliable stability(over 1000 cycles),en-abling the precise monitoring of human motion(e.g.,finger bending and wrist rotation).The flexible strain sensor based on this eutectogel is ex-pected to show promising prospects for medical monitoring,human-machine interaction,and industrial sensing applications.
基金supported by the National Key Research and Development of China(Grant No.2022YFB4601901)the National Natural Science Foundation of China(Grant Nos.12122202 and 12302078)the Postdoctoral Innovative Talents Support Program of China(Grant No.BX20230470).
文摘The demand for lightweight and multifunctional surface structure in high-end equipment is steadily growing.The harmonization between flexibility and electromagnetic tunability has become a significant subject for stealth morphing aircraft.This paper presents a microwave absorbing structure based on the kirigami configuration,aiming at improving the conformality with the negative Poisson’s ratio characteristic and expanding the radar stealth range with tunability.A precise electromagnetic reflectivity model of the impedance surface was established by the inversion method,and an integrated optimization algorithm was employed to optimize the structural parameters based on numerical analysis.Specimens composed of thermoplastic polyurethane elastic colloids and resistive materials were prepared to assess the in-plane mechanical tensile and electromagnetic absorption performances through experimental methods.The results indicate that the original absorption band spans 6.2-11.1 GHz,shifts to 8-18 GHz with stretching at a panel rotation angle of 16°,and remains nearly constant for further stretching.The specimens adhere to complex curved surfaces well in experiments and maintain the electromagnetic absorption performance compared with flat surfaces.This research offers a valuable reference for designing electromagnetic stealth structures that are highly stretchable and adjustable.
