OaAs has been widely used to fabricate a variety of optoelectronic devices by virtue of its superior performance, and it is very important to accurately measure its electrical and optical properties. In this study, a ...OaAs has been widely used to fabricate a variety of optoelectronic devices by virtue of its superior performance, and it is very important to accurately measure its electrical and optical properties. In this study, a semi- insulation （SI） GaAs wafer is investigated by the terahertz （THz） non-destructive testing technology. Using an air biased coherent generation and detection THz time domain spectroscopy system, the THz time domain waveform and spectrum of SI-GaAs are obtained by the time domain spectroscopy module, and its optical- electrical characteristics including complex refractive index, permittivity and dielectric loss angle are calculated. Its carrier lifetime is measured by the optical-pump THz-probe module, and the THz pulse induced intervalley scattering in photo-excited SI-GaAs is discussed.展开更多
As the main load bearing component,the steel strand has a significant impact on the safety of civil infrastructure.Real-time monitoring of steel strand stress distribution throughout the damage process is an impor-tan...As the main load bearing component,the steel strand has a significant impact on the safety of civil infrastructure.Real-time monitoring of steel strand stress distribution throughout the damage process is an impor-tant aspect of civil infrastructure health assessment.Hence,this study proposes an optical-electrical co-sensing(OECS)smart steel strand with the DOFS and CCFPI embedded in.It can simultaneously measure small strains in the initial damage phase with high accuracy and obtain information in the large deformation phase with relatively low precision.Several experiments were carried out to test its sensing performance.It shows both DOFS and CCFPI have good linearity,repeatability and hysteresis.In comparison to DOFS,CCFPI has a relatively lower accuracy and resolution,but a large enough measurement range to tolerate the large strain in the event of a steel strand failure.To verify the reliability of the proposed smart steel strand in real structures,the strand strain distribution in the full damage process of bonded prestressed beams under four-point bending loading was monitored using the smart steel strand as a prestressing tendon.The strain measured by the OECS steel strand is shown to reflect the deformation and stiffness variation of prestressed beams under different load.展开更多
Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic ...Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.展开更多
The achievement of electrically pumped lasers with smaller and more compact physical dimensions is expected to be crucial for future optical information processing,optical storage,and photonic integrated circuits.Howe...The achievement of electrically pumped lasers with smaller and more compact physical dimensions is expected to be crucial for future optical information processing,optical storage,and photonic integrated circuits.However,developing laser devices upon electrical injection remains challenging due to stability issues,significant non-radiative losses,and severe Joule heating effects.Herein,we exhibit an ultralow-threshold low-dimensional perovskite microlaser coated with Au nanoparticles(AuNPs),which enables the optimization of its lasing properties upon optical pumping synchronized with current injection at ambient temperature.The threshold value is considerably reduced to 8.6μJ/cm^(2),which is approximately 44%lower than that of the pristine one.The microlaser incorporates size-optimized AuNPs that simultaneously enhance perovskite's lasing performance and electrical properties,particularly enabling a current injection of approximately 2.98 kA/cm^(2).Besides,AuNPs can accelerate hot-carrier cooling in perovskites,thereby reducing non-radiative recombination losses and mitigating Joule heating effects.The microlaser thresholds show progressive reduction with increasing electrical assist fraction.This study underscores that the ultimate goal of realizing electrically driven perovskite microlasers may eventually become a reality,paving a promising avenue toward the further development of electrically pumped microlaser diodes.展开更多
The endurance limitation of unmanned aerial vehicles(UAVs)is a critical challenge hindering their widespread application.Laser Wireless Power Transfer(LWPT)technology,with its advantages including long transmission di...The endurance limitation of unmanned aerial vehicles(UAVs)is a critical challenge hindering their widespread application.Laser Wireless Power Transfer(LWPT)technology,with its advantages including long transmission distances and high power,presents a promising solution for energy supplementation.Nevertheless,in flight environments,LWPT systems encounter multiple challenges-spillover losses arising from beam spot-to-photovoltaic(PV)array mismatch due to varying transmission distances and electric mismatch losses caused by non-uniform irradiation induced by changes in UAV attitude.This paper develops a‘‘transmitter-beam distribution-PV array’’coupled model to simulate the optical-thermal-electrical multi-physics coupling characteristics of the PV array,considering varying transmission distances,pointing errors,and attitudes.Furthermore,a zoom system based on a dynamic beam waist adjustment method is proposed to optimize the beam waist radius for varying transmission distances,thereby effectively reducing spillover loss.Results indicate that the zoom system improves cut-off efficiency and extends the effective power transmission range compared to a fixed-focus system.While the received power loss from normal deviation follows the expected geometric cosine law,the study reveals that the radial deviation angle significantly exacerbates electrical mismatch.When the radial deviation angle reaches a maximum of 45◦,the mismatch loss rate attains 32%,leading to a 13.74%decrease in output power due to non-uniform sub-module activation.Under pointing error conditions(20 mm,45◦),system efficiency decreased by 48%.The findings of this study are valuable for achieving efficient power transfer for UAV-based LWPT systems.展开更多
In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based o...In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based on electronic transistor and von Neumann architecture cannot satisfy such an inconceivable demand due to the unsustainability of Moore’s Law and the failure of Dennard’s scaling rules.Fortunately,analog optical computing offers an alternative way to release unprecedented computational capability to accelerate varies computing drained tasks.In this article,the challenges of the modern computing technologies and potential solutions are briefly explained in Chapter 1.In Chapter 2,the latest research progresses of analog optical computing are separated into three directions:vector/matrix manipulation,reservoir computing and photonic Ising machine.Each direction has been explicitly summarized and discussed.The last chapter explains the prospects and the new challenges of analog optical computing.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 61575161 and 61427814the National Basic Research Program of China under Grant No 2014CB339800+1 种基金the Foundation of Shaanxi Key Science and Technology Innovation Team under Grant No 2014KTC-13the Special Financial Grant from the China Postdoctoral Science Foundation under Grant No 2013T60883
文摘OaAs has been widely used to fabricate a variety of optoelectronic devices by virtue of its superior performance, and it is very important to accurately measure its electrical and optical properties. In this study, a semi- insulation （SI） GaAs wafer is investigated by the terahertz （THz） non-destructive testing technology. Using an air biased coherent generation and detection THz time domain spectroscopy system, the THz time domain waveform and spectrum of SI-GaAs are obtained by the time domain spectroscopy module, and its optical- electrical characteristics including complex refractive index, permittivity and dielectric loss angle are calculated. Its carrier lifetime is measured by the optical-pump THz-probe module, and the THz pulse induced intervalley scattering in photo-excited SI-GaAs is discussed.
基金National Natural Science Foundation of China[52178282].
文摘As the main load bearing component,the steel strand has a significant impact on the safety of civil infrastructure.Real-time monitoring of steel strand stress distribution throughout the damage process is an impor-tant aspect of civil infrastructure health assessment.Hence,this study proposes an optical-electrical co-sensing(OECS)smart steel strand with the DOFS and CCFPI embedded in.It can simultaneously measure small strains in the initial damage phase with high accuracy and obtain information in the large deformation phase with relatively low precision.Several experiments were carried out to test its sensing performance.It shows both DOFS and CCFPI have good linearity,repeatability and hysteresis.In comparison to DOFS,CCFPI has a relatively lower accuracy and resolution,but a large enough measurement range to tolerate the large strain in the event of a steel strand failure.To verify the reliability of the proposed smart steel strand in real structures,the strand strain distribution in the full damage process of bonded prestressed beams under four-point bending loading was monitored using the smart steel strand as a prestressing tendon.The strain measured by the OECS steel strand is shown to reflect the deformation and stiffness variation of prestressed beams under different load.
基金supported financially by the National Key Research and Development Program of China (No. 2016YFB1102303)the National Basic Research Program of China (973 Program) (No. 2015CB352001)the National Natural Science Foundation of China(No. 61378060)
文摘Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.
基金supported by the National Natural Science Foundation of China (12374257)the Outstanding Doctoral Dis-sertation in Nanjing University of Aeronautics and Astronautics (BCXJ23-15)+1 种基金the Interdisciplinary Innovation Fund for Doctoral Students of Nanjing University of Aeronautics and Astronautics (KXKCXJJ202406)the Postgraduate Research&Practice Innovation Program of Jiangsu Province (KYCX25_0638)。
文摘The achievement of electrically pumped lasers with smaller and more compact physical dimensions is expected to be crucial for future optical information processing,optical storage,and photonic integrated circuits.However,developing laser devices upon electrical injection remains challenging due to stability issues,significant non-radiative losses,and severe Joule heating effects.Herein,we exhibit an ultralow-threshold low-dimensional perovskite microlaser coated with Au nanoparticles(AuNPs),which enables the optimization of its lasing properties upon optical pumping synchronized with current injection at ambient temperature.The threshold value is considerably reduced to 8.6μJ/cm^(2),which is approximately 44%lower than that of the pristine one.The microlaser incorporates size-optimized AuNPs that simultaneously enhance perovskite's lasing performance and electrical properties,particularly enabling a current injection of approximately 2.98 kA/cm^(2).Besides,AuNPs can accelerate hot-carrier cooling in perovskites,thereby reducing non-radiative recombination losses and mitigating Joule heating effects.The microlaser thresholds show progressive reduction with increasing electrical assist fraction.This study underscores that the ultimate goal of realizing electrically driven perovskite microlasers may eventually become a reality,paving a promising avenue toward the further development of electrically pumped microlaser diodes.
基金supported by the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(Project No.CUSF-DH-D-2024029)additionally,it receives support from the Opening Project of State Key Laboratory of Space Power Sources under National Key Research and Development Program of China(YF07050124F1268).
文摘The endurance limitation of unmanned aerial vehicles(UAVs)is a critical challenge hindering their widespread application.Laser Wireless Power Transfer(LWPT)technology,with its advantages including long transmission distances and high power,presents a promising solution for energy supplementation.Nevertheless,in flight environments,LWPT systems encounter multiple challenges-spillover losses arising from beam spot-to-photovoltaic(PV)array mismatch due to varying transmission distances and electric mismatch losses caused by non-uniform irradiation induced by changes in UAV attitude.This paper develops a‘‘transmitter-beam distribution-PV array’’coupled model to simulate the optical-thermal-electrical multi-physics coupling characteristics of the PV array,considering varying transmission distances,pointing errors,and attitudes.Furthermore,a zoom system based on a dynamic beam waist adjustment method is proposed to optimize the beam waist radius for varying transmission distances,thereby effectively reducing spillover loss.Results indicate that the zoom system improves cut-off efficiency and extends the effective power transmission range compared to a fixed-focus system.While the received power loss from normal deviation follows the expected geometric cosine law,the study reveals that the radial deviation angle significantly exacerbates electrical mismatch.When the radial deviation angle reaches a maximum of 45◦,the mismatch loss rate attains 32%,leading to a 13.74%decrease in output power due to non-uniform sub-module activation.Under pointing error conditions(20 mm,45◦),system efficiency decreased by 48%.The findings of this study are valuable for achieving efficient power transfer for UAV-based LWPT systems.
文摘In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based on electronic transistor and von Neumann architecture cannot satisfy such an inconceivable demand due to the unsustainability of Moore’s Law and the failure of Dennard’s scaling rules.Fortunately,analog optical computing offers an alternative way to release unprecedented computational capability to accelerate varies computing drained tasks.In this article,the challenges of the modern computing technologies and potential solutions are briefly explained in Chapter 1.In Chapter 2,the latest research progresses of analog optical computing are separated into three directions:vector/matrix manipulation,reservoir computing and photonic Ising machine.Each direction has been explicitly summarized and discussed.The last chapter explains the prospects and the new challenges of analog optical computing.
