The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave...The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.展开更多
In this article, unique spectral features of short-wave infrared band of 1 μm–3 μm, and various applications related to the photodetectors and focal plane arrays in this band, are introduced briefly. In addition, t...In this article, unique spectral features of short-wave infrared band of 1 μm–3 μm, and various applications related to the photodetectors and focal plane arrays in this band, are introduced briefly. In addition, the different material systems for the devices in this band are outlined. Based on the background, the development of lattice-matched and wavelengthextended InGaAs photodetectors and focal plane arrays, including our continuous efforts in this field, are reviewed. These devices are concentrated on the applications in spectral sensing and imaging, exclusive of optical fiber communication.展开更多
The Qulong deposit in Tibet is one of the largest porphyry copper-molybdenum deposits in China.We used short-wave infrared(SWIR)spectroscopy to examine the spectral characteristics of the extensively developed chlorit...The Qulong deposit in Tibet is one of the largest porphyry copper-molybdenum deposits in China.We used short-wave infrared(SWIR)spectroscopy to examine the spectral characteristics of the extensively developed chlorite in this deposit.X-ray diffraction and electron microprobe analyses were used for phase identification and to obtain the chemical composition,ion substitution relationships,and formation environment of the chlorite.SWIR spectral parameters were applied to detect the hydrothermal centers.The results indicate that the wavelength of the absorption feature for Qulong chlorite Fe-OH(Pos2250)range from 2240 to 2268.4 nm;the chlorite substitution relationships are dominated by Mg-Fe substitution at the octahedral sites together with Al;-Si substitution at the tetrahedral sites;the chlorite formation temperatures range within the medium-low temperature hydrothermal alteration range from 164 to 281°C,with an average value of 264℃;the wavelength of the chlorite peak position for Fe-OH(2250 nm)absorption and its chemical composition are positively correlated with Al^(Ⅵ),Fe+Al^(Ⅵ),Fe/(Fe+Mg),Fe,and Fe+Al^(Ⅳ)but negatively correlated with Mg and Mg/(Fe+Mg);and the wavelength associated with the chlorite Fe-OH(2250 nm)absorption feature is positively correlated with the temperature at which the chlorite formed.These correlations indicate that more Fe and Al^(Ⅵ)ions and fewer Mg ions at the octahedral sites of chlorite lead to a longer the wavelength of the chlorite Fe-OH(2250 nm)absorption feature and a higher chlorite formation temperature.The wavelength of the Qulong chlorite Fe-OH(2250 nm)absorption feature(>2252 nm)can thus serve as an exploration indicator to guide the detection of hydrothermal centers in porphyry copper deposits.The results of the study indicate that the mineralogical and SWIR spectral characteristics of chlorite are significant indicators for locating hydrothermal centers within porphyry deposits.展开更多
Fructus cnidii （Chinese name shechuangzi） is the fruit produced by Cnidium monnieri （L.） Cusson （Umbelliferae）. It is a perennial herb that is used to treat skin-related diseases and gynecopathyell. Recent pharm...Fructus cnidii （Chinese name shechuangzi） is the fruit produced by Cnidium monnieri （L.） Cusson （Umbelliferae）. It is a perennial herb that is used to treat skin-related diseases and gynecopathyell. Recent pharmacological studies have revealed crude extracts or components isolated from fructus cnidii possess antiallergic, antipruritic, antidermatophytic, antibacterial, antifungal, and antiosteoporotic activities. Osthole and imperatorin are the major compounds present in shechuangzi. They are often used as standards for the evaluation of the quality of shechuangzi products.展开更多
The complete discrimination system for polynomial method is applied to the long-short-wave interaction system to obtain the classifications of single traveling wave solutions. Compared with the solutions given by the ...The complete discrimination system for polynomial method is applied to the long-short-wave interaction system to obtain the classifications of single traveling wave solutions. Compared with the solutions given by the （G~/G）-expansion method, we gain some new solutions.展开更多
In this paper, the Lie symmetry analysis and generalized symmetry method are performed for a short-wave model. The symmetries for this equation are given, and the phase portraits of the traveling wave systems are anal...In this paper, the Lie symmetry analysis and generalized symmetry method are performed for a short-wave model. The symmetries for this equation are given, and the phase portraits of the traveling wave systems are analyzed using the bifurcation theory of dynamical systems. The exact parametric representations of four types of traveling wave solutions are obtained.展开更多
The 10 920 stress indicators collected so far by the WSM (World Stress Map) project represent the observed ori-entations of the maximum horizontal principal stress (sHmax) in a certain region. Assuming that the long-w...The 10 920 stress indicators collected so far by the WSM (World Stress Map) project represent the observed ori-entations of the maximum horizontal principal stress (sHmax) in a certain region. Assuming that the long-wave component of sHmax is expressed by the absolute direction of plate motions, we can get the relative orientation and the magnitude of the short-wave component resulted from the local tectonic process or other factors with vector analytical technique. The global surface was divided into basic element bins by 2.52.5 dimensions and the WSM indicators were statistically analyzed for each element by weight coefficient method in order to determine the mean orientation of the stress. We calculated the long-wave component of the global stress field using HS2-NUVEL1 model. The relative magnitude or the direction limitation of short-wave component, which reflect the local contribution to the observed stresses, was determined by the angle between the mean sHmax and the orien-tation of the long-wave component. The results of this paper show that the contribution of either the long-wave component or the short-wave component is approximately equal to most of the global plates on the basis of the mean effect of the observed stresses. For some of continental regions, the local active tectonics plays an important role in the observed stresses and controls the generation and occurrence of earthquakes.展开更多
Compared with the conventional first near-infrared(NIR-I,700900 nm)window,the short-wave infrared region(SWIR,900—1700nm)possesses the merits of the increasing tissue penetration depths and the suppression of scatter...Compared with the conventional first near-infrared(NIR-I,700900 nm)window,the short-wave infrared region(SWIR,900—1700nm)possesses the merits of the increasing tissue penetration depths and the suppression of scattering background,leading to great potential for in vivo imaging.Based on the limitations of the common spectral domain,and the superiority of the time-dimension,time-resolved imaging eliminates the auto-fuorescence in the biological tissue,thus supporting higher signal-to-noise ratio and sensitivities.The imaging technique is not affected by the difference in tissue composition or thickness and has the practical value of quan-titative in vivo detection.Almost all the relevant time-resolved imaging was carried out around lanthanide-doped upconversion nanomaterials,owing to the advantages of ultralong luminescence lifetime,excellent photostability,controllable morphology,easy surface modification and various strategies of regulating lifetime.Therefore,this review presents the research progress of SWIR time-resolved imaging technology based on nanomaterials doped with lanthanide ions as luminescence centers in recent years.展开更多
The trans-media transmission of quantum pulse is one of means of free-space transmission which can be applied in continuous-variable quantum key distribution(CVQKD)system.In traditional implementations for atmospheric...The trans-media transmission of quantum pulse is one of means of free-space transmission which can be applied in continuous-variable quantum key distribution(CVQKD)system.In traditional implementations for atmospheric channels,the 1500-to-1600-nm pulse is regarded as an ideal quantum pulse carrier.However,the underwater transmission of this pulses tends to suffer from severe attenuation,which inevitably deteriorates the security of the whole CVQKD system.In this paper,we propose an alternative scheme for implementations of CVQKD over satellite-to-submarine channels.We estimate the parameters of the trans-media channels,involving atmosphere,sea surface and seawater and find that the shortwave infrared performs well in the above channels.The 450-nm pulse is used for generations of quantum signal carriers to accomplish quantum communications through atmosphere,sea surface and seawater channels.Numerical simulations show that the proposed scheme can achieve the transmission distance of 600 km.In addition,we demonstrate that non-Gaussian operations can further lengthen its maximal transmission distance,which contributes to the establishment of practical global quantum networks.展开更多
InP quantum dots(QDs)have been a major building block of modern display technology due to their high photoluminescence quantum yield(PLQY)in the visible spectrum,superior stability,and eco-friendly composition.However...InP quantum dots(QDs)have been a major building block of modern display technology due to their high photoluminescence quantum yield(PLQY)in the visible spectrum,superior stability,and eco-friendly composition.However,their applications at short-wave infrared(SWIR)have been hindered by their low efficiency.Here,we report the synthesis of efficient and SWIR-emitting InP QDs by precisely controlling the InP core nucleation using a low-cost ammonia phosphorus precursor,while avoiding size-limiting ZnCl_(2) for effective copper doping.Subsequent epitaxial growth of a lattice-matched ZnSe/ZnS multishell enhanced the QD sphericity and surface smoothness and yielded a record PLQY of 66% with an emission peak at 960 nm.When QDs were integrated as the high-refractive-index luminescent core of a liquid waveguide-based luminescent solar concentrator(LSC),the device achieved an optical efficiency of 7.36%.This performance arises from their high PLQY,spectral alignment with the responsivity peak of silicon solar cells,and the optimized core/cladding waveguide structure.These results highlight the potential of InP QDs as a promising nanomaterial for SWIR emission and applications.展开更多
In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low ...In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.展开更多
The trivalent ytterbium(Yb^(3+))ion has been extensively used as an emitter in short-wave infrared(SWIR)lasers,a sensitizer to activate other lanthanide ions for up-conversion luminescence,and a spectral converter in ...The trivalent ytterbium(Yb^(3+))ion has been extensively used as an emitter in short-wave infrared(SWIR)lasers,a sensitizer to activate other lanthanide ions for up-conversion luminescence,and a spectral converter in Ln^(3+)-Yb^(3+)doubly doped quantum cutting phosphors.Here we report a new function of the Yb^(3+)ion—as an efficient emitting center for SWIR persistent luminescence.We have developed the first real SWIR persistent phosphor,MgGeO3:Yb^(3+),which exhibits very-long persistent luminescence at around 1000 nm for longer than 100 h.The MgGeO3:Yb^(3+)phosphor is spectrally transparent to visible/near-infrared light(~400–900 nm)and is a promising ultraviolet-to-SWIR spectral convertor.The MgGeO3:Yb^(3+)phosphor also exhibits a photostimulated persistent luminescence capability,where the SWIR persistent emission in an ultraviolet-light pre-irradiated sample can be rejuvenated by low-energy light(white or red light)stimulation.The MgGeO3:Yb^(3+)phosphor is expected to have promising applications in biomedical imaging,night-vision surveillance and photovoltaics.展开更多
We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-chan...We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-channel SWIR multispectral detector has been fabricated for demonstration.Sixteen different narrowband response spectra are acquired on a 64×64 pixels detector chip by four times combinatorial etching processes.The peak of the response spectra varies from1450 to 1666 nm with full width at half-maximum of 24 nm on average.The size of the SWIR multispectral detection system is remarkably reduced to a 2 mm^(2) detector chip.展开更多
Compared with borates, carbonates, nitrates and phosphates, sulfates have been ignored as nonlinear optical(NLO) materials for a long time. Recently, researchers started to realize sulfates which have the potential as...Compared with borates, carbonates, nitrates and phosphates, sulfates have been ignored as nonlinear optical(NLO) materials for a long time. Recently, researchers started to realize sulfates which have the potential as NLO materials, and synthesized some sulfate NLO materials by the water solution method and solvothermal method. However, all these sulfate NLO materials have the same problem of low thermal stability. Here, we synthesized a new Cs4 Mg6(SO4)8, which crystallizes in the orthorhombic space group P212121 with a = 9.102, b = 9.955, c = 16.127 ?, V = 1461.3 ?3, Z = 2, F(000) = 1352, μ = 5.777 mm-1, R = 0.0213 and wR = 0.0480. The single crystal structure can be described as a three-dimensional framework constructed by MgO6 octahedra and SO4 tetrahedra. Relevant optical measurements indicate that Cs4 Mg6(SO4)8 is short-wave ultraviolet transparent and has a moderate second harmonic generation response. Theoretical calculations by the CASTEP package reveal that S–O groups are NLO-active anionic groups. Significantly, Cs4 Mg6(SO4)8 has high thermal stability up to 781 ℃ based on thermal analyses. We believe that our work will provide a new strategy for researchers to develop new sulfate short-wave ultraviolet NLO materials of high thermal stability.展开更多
This paper focuses on performance of several efficient and accurate numerical methods for the long-wave short-wave interaction equations in the semiclassical limit regime. The key features of the proposed methods are ...This paper focuses on performance of several efficient and accurate numerical methods for the long-wave short-wave interaction equations in the semiclassical limit regime. The key features of the proposed methods are based on:(i) the utilization of the first-order or second-order time-splitting method to the nonlinear wave interaction equations;(ii) the ap-plication of Fourier pseudo-spectral method or compact finite difference approximation to the linear subproblem and the spatial derivatives;(iii) the adoption of the exact integration of the nonlinear subproblems and the ordinary differential equations in the phase space. The numerical methods under study are efficient, unconditionally stable and higher-order accurate, they are proved to preserve two invariants including the position density in L^1. Numerical results are reported for case studies with different types of initial data, these results verify the conservation laws in the discrete sense, show the dependence of the numerical solution on the time-step, mesh-size and dispersion parameter ε, and demonstrate the behavior of nonlinear dispersive waves in the semi-classical limit regime.展开更多
Dispersive magnetohydrodynamic (MHD) waves with short-wavelength modification have an important role in transforming energy from waves into particles.In this paper,based on the two-fluid mode,a dispersion equation,inc...Dispersive magnetohydrodynamic (MHD) waves with short-wavelength modification have an important role in transforming energy from waves into particles.In this paper,based on the two-fluid mode,a dispersion equation,including the short-wavelength effect,and its exact solution are presented.The outcome is responsible for the short-wavelength modification versions of the three ideal MHD modes (i.e.the fast,slow and Alfve'n).The results show that the fast and Alfve'n modes are modified considerably by the shortwavelength effect mainly in the quasi-parallel and quasi-perpendicular propagation directions,respectively,while the slow mode can be affected by the short-wavelength effect in all propagation directions.On the other hand,the dispersive modification occurs primarily in the finite-β regime of 0.001 < β < 1 for the fast mode and in the high-β regime of 0.1 < β < 10 for the slow mode.For the Alfve'n mode,the dispersive modification occurs from the low-β regime of β < 0.001 through the high-β regime of β > 1.展开更多
针对天基短波红外图像中弱小目标易被云层、地表杂波淹没,且在低信杂比条件下检测困难的问题,提出一种融合安德森加速的自正则化加权稀疏模型(Self-Regularized Weighted Sparse,SRWS)与相对局部对比度(Relative Local Contrast Measure...针对天基短波红外图像中弱小目标易被云层、地表杂波淹没,且在低信杂比条件下检测困难的问题,提出一种融合安德森加速的自正则化加权稀疏模型(Self-Regularized Weighted Sparse,SRWS)与相对局部对比度(Relative Local Contrast Measure,RLCM)的改进检测方法。通过引入安德森加速机制,显著降低了背景估计的计算复杂度,利用背景残差图和RLCM实现了多尺度目标检测性。实验结果表明,本文算法在复杂背景下仍保持优异性能,接收者操作曲线下面积(Area Under Curve,AUC)最高达0.950,最低不低于0.842;信杂比增益(Signal-to-Clutter Ratio Gain,SCRG)显著优于红外图像块(Infrared Patch Image,IPI)、局部对比度法(Local Contrast Measure,LCM)等传统方法。本研究有效提升了天基短波红外弱小目标的检测精度与稳定性,为复杂背景下的遥感目标检测提供了可靠的解决方案。展开更多
基金Supported by the Short-wave Infrared Camera Systems(B025F40622024)。
文摘The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402400)the National Natural Science Foundation of China(Grant Nos.61675225,61605232,and 61775228)the Shanghai Rising-Star Program,China(Grant No.17QA1404900)
文摘In this article, unique spectral features of short-wave infrared band of 1 μm–3 μm, and various applications related to the photodetectors and focal plane arrays in this band, are introduced briefly. In addition, the different material systems for the devices in this band are outlined. Based on the background, the development of lattice-matched and wavelengthextended InGaAs photodetectors and focal plane arrays, including our continuous efforts in this field, are reviewed. These devices are concentrated on the applications in spectral sensing and imaging, exclusive of optical fiber communication.
基金funded by Science and Technology Project of Tibet Autonomous Region(Grant Nos.XZ201801-GB-01XZ202102YD0024C)+2 种基金The Second Round of Comprehensive Investigation and Research on the Qinghai-Tibet Plateau(Grant No.2019QZKK0806)National Natural Science Foundation of China(Grant No.42002097)Demonstration Research on Alteration Mapping using Short-wave Infrared and Thermal Infrared Hyperspectral Technologies(Grant No.KK2102)。
文摘The Qulong deposit in Tibet is one of the largest porphyry copper-molybdenum deposits in China.We used short-wave infrared(SWIR)spectroscopy to examine the spectral characteristics of the extensively developed chlorite in this deposit.X-ray diffraction and electron microprobe analyses were used for phase identification and to obtain the chemical composition,ion substitution relationships,and formation environment of the chlorite.SWIR spectral parameters were applied to detect the hydrothermal centers.The results indicate that the wavelength of the absorption feature for Qulong chlorite Fe-OH(Pos2250)range from 2240 to 2268.4 nm;the chlorite substitution relationships are dominated by Mg-Fe substitution at the octahedral sites together with Al;-Si substitution at the tetrahedral sites;the chlorite formation temperatures range within the medium-low temperature hydrothermal alteration range from 164 to 281°C,with an average value of 264℃;the wavelength of the chlorite peak position for Fe-OH(2250 nm)absorption and its chemical composition are positively correlated with Al^(Ⅵ),Fe+Al^(Ⅵ),Fe/(Fe+Mg),Fe,and Fe+Al^(Ⅳ)but negatively correlated with Mg and Mg/(Fe+Mg);and the wavelength associated with the chlorite Fe-OH(2250 nm)absorption feature is positively correlated with the temperature at which the chlorite formed.These correlations indicate that more Fe and Al^(Ⅵ)ions and fewer Mg ions at the octahedral sites of chlorite lead to a longer the wavelength of the chlorite Fe-OH(2250 nm)absorption feature and a higher chlorite formation temperature.The wavelength of the Qulong chlorite Fe-OH(2250 nm)absorption feature(>2252 nm)can thus serve as an exploration indicator to guide the detection of hydrothermal centers in porphyry copper deposits.The results of the study indicate that the mineralogical and SWIR spectral characteristics of chlorite are significant indicators for locating hydrothermal centers within porphyry deposits.
基金Supported by the Talented Young Pressional Foundation of Jilin Province(No 2005123)
文摘Fructus cnidii （Chinese name shechuangzi） is the fruit produced by Cnidium monnieri （L.） Cusson （Umbelliferae）. It is a perennial herb that is used to treat skin-related diseases and gynecopathyell. Recent pharmacological studies have revealed crude extracts or components isolated from fructus cnidii possess antiallergic, antipruritic, antidermatophytic, antibacterial, antifungal, and antiosteoporotic activities. Osthole and imperatorin are the major compounds present in shechuangzi. They are often used as standards for the evaluation of the quality of shechuangzi products.
基金Project supported by the Scientific Research Fund of Education Department of Heilongjiang Province of China (Grant No.12531475)
文摘The complete discrimination system for polynomial method is applied to the long-short-wave interaction system to obtain the classifications of single traveling wave solutions. Compared with the solutions given by the （G~/G）-expansion method, we gain some new solutions.
基金Project supported by the Foundation of Guangxi Key Laboratory of Trusted Software, the Guangxi Natural Science Foundation, China (Grant No. 2011GXNSFA018134)the National Natural Science Foundation of China (Grant Nos. 11161013 and 61004101)
文摘In this paper, the Lie symmetry analysis and generalized symmetry method are performed for a short-wave model. The symmetries for this equation are given, and the phase portraits of the traveling wave systems are analyzed using the bifurcation theory of dynamical systems. The exact parametric representations of four types of traveling wave solutions are obtained.
基金MOST contract of 2001BA601B02 and State Natural Science Foundation of China (49804006).
文摘The 10 920 stress indicators collected so far by the WSM (World Stress Map) project represent the observed ori-entations of the maximum horizontal principal stress (sHmax) in a certain region. Assuming that the long-wave component of sHmax is expressed by the absolute direction of plate motions, we can get the relative orientation and the magnitude of the short-wave component resulted from the local tectonic process or other factors with vector analytical technique. The global surface was divided into basic element bins by 2.52.5 dimensions and the WSM indicators were statistically analyzed for each element by weight coefficient method in order to determine the mean orientation of the stress. We calculated the long-wave component of the global stress field using HS2-NUVEL1 model. The relative magnitude or the direction limitation of short-wave component, which reflect the local contribution to the observed stresses, was determined by the angle between the mean sHmax and the orien-tation of the long-wave component. The results of this paper show that the contribution of either the long-wave component or the short-wave component is approximately equal to most of the global plates on the basis of the mean effect of the observed stresses. For some of continental regions, the local active tectonics plays an important role in the observed stresses and controls the generation and occurrence of earthquakes.
基金the National Natural Science Foundation of China(No.81971704)the National Key ResearchandDevelopment Program of China(No.2017YFA0205304)the Translational Medicine Research Fund of National Facility for Translational Medicine(Shanghai)(No.TMSK-2021-117)。
文摘Compared with the conventional first near-infrared(NIR-I,700900 nm)window,the short-wave infrared region(SWIR,900—1700nm)possesses the merits of the increasing tissue penetration depths and the suppression of scattering background,leading to great potential for in vivo imaging.Based on the limitations of the common spectral domain,and the superiority of the time-dimension,time-resolved imaging eliminates the auto-fuorescence in the biological tissue,thus supporting higher signal-to-noise ratio and sensitivities.The imaging technique is not affected by the difference in tissue composition or thickness and has the practical value of quan-titative in vivo detection.Almost all the relevant time-resolved imaging was carried out around lanthanide-doped upconversion nanomaterials,owing to the advantages of ultralong luminescence lifetime,excellent photostability,controllable morphology,easy surface modification and various strategies of regulating lifetime.Therefore,this review presents the research progress of SWIR time-resolved imaging technology based on nanomaterials doped with lanthanide ions as luminescence centers in recent years.
基金supported by the National Natural Science Foundation of China(Grant Nos.62101180 and 61871407)the Key R&D Program of Hunan Province(Grant No.2022GK2016)+1 种基金the State Key Laboratory of High Performance Computing,National University of Defense Technology(Grant No.202101-25)the Fundamental Research Funds for the Central Universities(Grant No.531118010371)。
文摘The trans-media transmission of quantum pulse is one of means of free-space transmission which can be applied in continuous-variable quantum key distribution(CVQKD)system.In traditional implementations for atmospheric channels,the 1500-to-1600-nm pulse is regarded as an ideal quantum pulse carrier.However,the underwater transmission of this pulses tends to suffer from severe attenuation,which inevitably deteriorates the security of the whole CVQKD system.In this paper,we propose an alternative scheme for implementations of CVQKD over satellite-to-submarine channels.We estimate the parameters of the trans-media channels,involving atmosphere,sea surface and seawater and find that the shortwave infrared performs well in the above channels.The 450-nm pulse is used for generations of quantum signal carriers to accomplish quantum communications through atmosphere,sea surface and seawater channels.Numerical simulations show that the proposed scheme can achieve the transmission distance of 600 km.In addition,we demonstrate that non-Gaussian operations can further lengthen its maximal transmission distance,which contributes to the establishment of practical global quantum networks.
文摘InP quantum dots(QDs)have been a major building block of modern display technology due to their high photoluminescence quantum yield(PLQY)in the visible spectrum,superior stability,and eco-friendly composition.However,their applications at short-wave infrared(SWIR)have been hindered by their low efficiency.Here,we report the synthesis of efficient and SWIR-emitting InP QDs by precisely controlling the InP core nucleation using a low-cost ammonia phosphorus precursor,while avoiding size-limiting ZnCl_(2) for effective copper doping.Subsequent epitaxial growth of a lattice-matched ZnSe/ZnS multishell enhanced the QD sphericity and surface smoothness and yielded a record PLQY of 66% with an emission peak at 960 nm.When QDs were integrated as the high-refractive-index luminescent core of a liquid waveguide-based luminescent solar concentrator(LSC),the device achieved an optical efficiency of 7.36%.This performance arises from their high PLQY,spectral alignment with the responsivity peak of silicon solar cells,and the optimized core/cladding waveguide structure.These results highlight the potential of InP QDs as a promising nanomaterial for SWIR emission and applications.
基金supported in part by the National Natural Science Foundation of China(Nos.62074134 and 62104205)in part by the National Key Research and Development Program of China(No.2018YFB2200103).
文摘In this work,a short-wave infrared(SWIR)n-MoSe_(2)/p-GeSn/n-germanium-on-insulator(GOI)heterojunction phototransistor(HPT)with Sn composition-graded GeSn base is proposed for improvement of overall performance at low cost.The Sn composition-graded GeSn base layers are grown using magnetron sputtering epitaxy technique for improvement of crystal quality with a high Sn content of 15.2%in the top layer,rendering the extension of the cutoff wavelength beyond 2400 nm and significant suppression of dark current.The enormous electron/hole injection ratio,resulting from the large bandgap offset between the MoSe_(2)emitter and the GeSn base,enables the harvesting of a high photocurrent gain of HPT.By optimizing the device parameters,a considerable responsivity of 23.79 A/W and an excellent specific detectivity of 8.24×10^(10)Jones at the peak wavelength of 2030 nm were achieved for the HPT with the dark current density of 261 mA/cm^(2)under the emitter-collector bias voltage of 1.0 V at room temperature.The fast response speed is obtained for the HPT in terms of rising/falling times of 2.8μs/9.3μs at 1550 nm,surpassing those of most van der Waals(vdW)junction-based devices.Those results demonstrate that GeSn HPTs are suitable for SWIR optoelectronic imaging and microwave photonics applications.
基金support from the National Science Foundation(CAREER DMR-0955908,DMR-1403929)support from the National Natural Science Foundation of China(no.81171463)support from the China Scholarship Council.
文摘The trivalent ytterbium(Yb^(3+))ion has been extensively used as an emitter in short-wave infrared(SWIR)lasers,a sensitizer to activate other lanthanide ions for up-conversion luminescence,and a spectral converter in Ln^(3+)-Yb^(3+)doubly doped quantum cutting phosphors.Here we report a new function of the Yb^(3+)ion—as an efficient emitting center for SWIR persistent luminescence.We have developed the first real SWIR persistent phosphor,MgGeO3:Yb^(3+),which exhibits very-long persistent luminescence at around 1000 nm for longer than 100 h.The MgGeO3:Yb^(3+)phosphor is spectrally transparent to visible/near-infrared light(~400–900 nm)and is a promising ultraviolet-to-SWIR spectral convertor.The MgGeO3:Yb^(3+)phosphor also exhibits a photostimulated persistent luminescence capability,where the SWIR persistent emission in an ultraviolet-light pre-irradiated sample can be rejuvenated by low-energy light(white or red light)stimulation.The MgGeO3:Yb^(3+)phosphor is expected to have promising applications in biomedical imaging,night-vision surveillance and photovoltaics.
基金supported by the National Natural Science Foundation of China(NSFC)(No.11874376)Shanghai Science and Technology Foundations(Nos.19DZ2293400 and 19ZR1465900)+1 种基金Shanghai Municipal Science and Technology Major Project(No.2019SHZDZX01)Chinese Academy of Sciences President’s International Fellowship Initiative(No.2021PT0007)。
文摘We demonstrate an ultra-compact short-wave infrared[SWIR]multispectral detector chip by monolithically integrating the narrowband Fabry–Perot microcavities array with the In Ga As detector focal plane array.A 16-channel SWIR multispectral detector has been fabricated for demonstration.Sixteen different narrowband response spectra are acquired on a 64×64 pixels detector chip by four times combinatorial etching processes.The peak of the response spectra varies from1450 to 1666 nm with full width at half-maximum of 24 nm on average.The size of the SWIR multispectral detection system is remarkably reduced to a 2 mm^(2) detector chip.
基金financially supported by the National Natural Science Foundation of China(21833010,21571178,21601188,51872297,51802321)。
文摘Compared with borates, carbonates, nitrates and phosphates, sulfates have been ignored as nonlinear optical(NLO) materials for a long time. Recently, researchers started to realize sulfates which have the potential as NLO materials, and synthesized some sulfate NLO materials by the water solution method and solvothermal method. However, all these sulfate NLO materials have the same problem of low thermal stability. Here, we synthesized a new Cs4 Mg6(SO4)8, which crystallizes in the orthorhombic space group P212121 with a = 9.102, b = 9.955, c = 16.127 ?, V = 1461.3 ?3, Z = 2, F(000) = 1352, μ = 5.777 mm-1, R = 0.0213 and wR = 0.0480. The single crystal structure can be described as a three-dimensional framework constructed by MgO6 octahedra and SO4 tetrahedra. Relevant optical measurements indicate that Cs4 Mg6(SO4)8 is short-wave ultraviolet transparent and has a moderate second harmonic generation response. Theoretical calculations by the CASTEP package reveal that S–O groups are NLO-active anionic groups. Significantly, Cs4 Mg6(SO4)8 has high thermal stability up to 781 ℃ based on thermal analyses. We believe that our work will provide a new strategy for researchers to develop new sulfate short-wave ultraviolet NLO materials of high thermal stability.
基金the the National Natural Science Foundation (Grant No. 11571181)the Natural Science Foundation of Jiangsu Province (Grant No. BK20171454)Qing Lan project, thank the reviewers for their many valuable suggestions. This work was partially done while the first author was visiting Beijing Computational Science Research Center from October 3, 2013 to March 3, 2014.
文摘This paper focuses on performance of several efficient and accurate numerical methods for the long-wave short-wave interaction equations in the semiclassical limit regime. The key features of the proposed methods are based on:(i) the utilization of the first-order or second-order time-splitting method to the nonlinear wave interaction equations;(ii) the ap-plication of Fourier pseudo-spectral method or compact finite difference approximation to the linear subproblem and the spatial derivatives;(iii) the adoption of the exact integration of the nonlinear subproblems and the ordinary differential equations in the phase space. The numerical methods under study are efficient, unconditionally stable and higher-order accurate, they are proved to preserve two invariants including the position density in L^1. Numerical results are reported for case studies with different types of initial data, these results verify the conservation laws in the discrete sense, show the dependence of the numerical solution on the time-step, mesh-size and dispersion parameter ε, and demonstrate the behavior of nonlinear dispersive waves in the semi-classical limit regime.
基金supported by the National Natural Science Foundation of China(10973043,41074107)National Basic Research Program of China(2011CB811402)
文摘Dispersive magnetohydrodynamic (MHD) waves with short-wavelength modification have an important role in transforming energy from waves into particles.In this paper,based on the two-fluid mode,a dispersion equation,including the short-wavelength effect,and its exact solution are presented.The outcome is responsible for the short-wavelength modification versions of the three ideal MHD modes (i.e.the fast,slow and Alfve'n).The results show that the fast and Alfve'n modes are modified considerably by the shortwavelength effect mainly in the quasi-parallel and quasi-perpendicular propagation directions,respectively,while the slow mode can be affected by the short-wavelength effect in all propagation directions.On the other hand,the dispersive modification occurs primarily in the finite-β regime of 0.001 < β < 1 for the fast mode and in the high-β regime of 0.1 < β < 10 for the slow mode.For the Alfve'n mode,the dispersive modification occurs from the low-β regime of β < 0.001 through the high-β regime of β > 1.
文摘针对天基短波红外图像中弱小目标易被云层、地表杂波淹没,且在低信杂比条件下检测困难的问题,提出一种融合安德森加速的自正则化加权稀疏模型(Self-Regularized Weighted Sparse,SRWS)与相对局部对比度(Relative Local Contrast Measure,RLCM)的改进检测方法。通过引入安德森加速机制,显著降低了背景估计的计算复杂度,利用背景残差图和RLCM实现了多尺度目标检测性。实验结果表明,本文算法在复杂背景下仍保持优异性能,接收者操作曲线下面积(Area Under Curve,AUC)最高达0.950,最低不低于0.842;信杂比增益(Signal-to-Clutter Ratio Gain,SCRG)显著优于红外图像块(Infrared Patch Image,IPI)、局部对比度法(Local Contrast Measure,LCM)等传统方法。本研究有效提升了天基短波红外弱小目标的检测精度与稳定性,为复杂背景下的遥感目标检测提供了可靠的解决方案。
