Short-wave infrared InGaAs photodetectors and focal plane arrays

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.

Application of Short-wave Near-infrared Reflectance Spectroscopy in Controlling Extract of Fructus Cnidii Using Supercritical Carbon Dioxide

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.

On the exact solutions to the long short-wave interaction system

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.

Lie symmetries and exact solutions for a short-wave model

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.

An analysis on short-wave components of the global stress field

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.

Mineralogical Characteristics and Short-wave Infrared Spectra of Chlorite as Indicators of Hydrothermal Centers: A Case Study of the Giant Porphyry Copper-Molybdenum Deposit at Qulong, Tibet

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.

Short-wave infrared continuous-variable quantum key distribution over satellite-to-submarine channels

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.

Time-Resolved Imaging in Short-Wave Infrared Region

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.

New function of the Yb^(3+) ion as an efficient emitter of persistent luminescence in the short-wave infrared

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.

Portable Analyzer for Rapid Analysis of Total Protein, Fat and Lactose Contents in Raw Milk Measured by Non-dispersive Short-wave Near-infrared Spectrometry

A novel portable analyzer for raw milk quality control during the material purchase at dairy plants was developed, by which the percentages（mass fraction） of main components including total protein, fat, and lactose of an unhomogenized milk sample could be determinated in 1 min with the help of non-dispersive short-wave near-infrared （NDSWNIR） spectrometry in a wavelength range from 600 nm to 1100 nm and multivariate calibration. The analyzer was designed with a single-beam optical system, which comprised a temperature control module, a multi-channel narrow-band light source（16 wavelengths）, a glass absorption cell with 15 mm sample thickness, a silicon photodiode detector, several compound lenses and a recorder module. A total of 80 raw milk samples were collected at a dairy farm twice a month for 4 months. The samples were scanned with a common UV-Vis-NIR spectrometer and analyzed according to China GB standard methods. The uninformative variables elimination（UVE） method was carried out on the spectrum data and the percentages of main components of all the samples to choose the peak emitting wavelength of each channel of the light source. Another 90 raw milk samples were collected from the same dairy farm thrice a month for 3 months. The samples were analyzed according to China GB standard methods and with the proposed analyzer. The percentages of the main components and the NDSWNIR absorption data of the samples were used for the construction and validation of the multivariate calibration model with partial least squares（PLS） method. The root-mean-square errors of prediction（RMSEP） of total protein, fat and lactose were 0.201, 0.172 and 0.247 and the coefficients of correlation（R） were 0.932, 0.981 and 0.933, respectively.

On-chip short-wave infrared multispectral detector based on integrated Fabry–Perot microcavities array

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.

A Short-wave UV Nonlinear Optical Sulfate of High Thermal Stability

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.

EFFICIENT AND ACCURATE NUMERICAL METHODS FOR LONG-WAVE SHORT-WAVE INTERACTION EQUATIONS IN THE SEMICLASSICAL LIMIT REGIME

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.

Exact solutions of dispersion equation for MHD waves with short-wavelength modification

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.

城市轨道交通轨面短波不平顺谱实测研究

针对城市轨道交通诱发的振动噪声问题,对轨面短波不平顺进行研究.首先,对上海市轨道交通线路轨面短波不平顺实测数据进行零均值化、剔除异常值、消除趋势项等预处理.其次,利用改进的协方差法计算得到轨面短波不平顺功率谱,分析轨道类型、曲线半径及钢轨接头对轨面短波不平顺功率谱分布规律的影响.然后,基于非线性最小二乘法对轨面短波不平顺谱进行拟合.最后,提出我国城市轨道交通轨面短波不平顺统计谱表达式.研究结果表明:直线段接头区轨面短波不平顺功率谱密度曲线在整个分析波长范围内具有较多特征峰值;直线段接头区上、下行短波不平顺功率谱密度值随波长的分布特征和数值相差不大,说明上、下行的轨面不平顺状态基本相同;钢轨的磨耗程度与曲线半径呈负相关,内、外轨面不平顺功率谱密度的差异随曲线半径的增大而减小,曲线半径是影响轨面不平顺状态的主要因素之一;线路类型对轨面短波不平顺功率谱的影响不大,不同曲线半径、焊接接头影响明显,在对轨道进行维护和养护时需关注小曲线半径区段以及焊接接头区段的不平顺状态.

高速铁路0.01~1 m波段高低轨道不平顺特性分析

随着我国高速铁路发展规模的不断扩大及运营速度的不断提升,轨道短波不平顺引起的振动与噪声问题日益严重。深入研究高速铁路短波不平顺的时域、频域与时频域特征,对精准掌握高速铁路轨道短波平顺状态及其引起的车-轨系统振动、伤损等一系列问题具有重要的参考价值。以某高速铁路实测0.01~1 m波段轨面高低不平顺数据为研究对象,经过数据预处理剔除异常值并消除趋势项后,对实测不平顺数据进行时域分析,得到该高铁线路短波不平顺数据的统计与分布特性。采用平均周期图法计算该高铁线路轨道短波不平顺功率谱密度,应用非线性最小二乘拟合优化算法进行拟合,提出高速铁路轨道短波不平顺谱。从时频域角度对该段数据进行经验模态分解与希尔伯特变换,分析该高铁线路短波不平顺的希尔伯特谱与边际谱。研究结果表明:该高铁线路轨道短波不平顺数据各统计量幅值都较小,且近似服从正态分布;该高铁线路轨道短波不平顺功率谱密度存在与钢轨波磨有关的多个周期性成分,提出的高速铁路短波不平顺谱函数能够很好地对实测功率谱密度进行拟合,且拟合效果优于经典的SATO建议的短波谱与50 kg/m钢轨的短波谱;对该高铁线路轨道可能存在的短波病害进行识别与定位,时频域分析的方法可以较好地应用于高速铁路轨道平顺性的分析与日常的管理维护。

SWIR FluorescenceImaging In Vivo Monitoring and Evaluating Implanted M2 Macrophages in Skeletal Muscle Regeneration

Skeletal muscle has a robust regeneration ability that is impaired by severe injury,disease,and aging.resulting in a decline in skeletal muscle function.Therefore,improving skeletal muscle regeneration is a key challenge in treating skeletal muscle-related disorders.Owing to their significant role in tissue regeneration,implantation of M2 macrophages(M2MФ)has great potential for improving skeletal muscle regeneration.Here,we present a short-wave infrared(SWIR)fluorescence imaging technique to obtain more in vivo information for an in-depth evaluation of the skeletal muscle regeneration effect after M2MФtransplantation.SWIR fluorescence imaging was employed to track implanted M2MФin the injured skeletal muscle of mouse models.It is found that the implanted M2MФaccumulated at the injury site for two weeks.Then,SWIR fluorescence imaging of blood vessels showed that M2MФimplantation could improve the relative perfusion ratio on day 5(1.09±0.09 vs 0.85±0.05;p=0.01)and day 9(1.38±0.16 vs 0.95±0.03;p=0.01)post-injury,as well as augment the degree of skeletal muscle regencration on day 13 post-injury.Finally,multiple linear regression analyses determined that post-injury time and relative perfusion ratio could be used as predictive indicators to evaluate skeletal muscle regeneration.These results provide more in vivo details about M2MФin skeletal muscle regeneration and confirm that M2MФcould promote angiogenesis and improve the degree of skeletal muscle repair,which will guide the research and development of M2MФimplantation to improve skeletal muscle regeneration.

High-performance GaSb planar PN junction detector

This paper examines GaSb short-wavelength infrared detectors employing planar PN junctions. The fabrication was based on the Zn diffusion process and the diffusion temperature was optimized. Characterization revealed a 50% cut-off wavelength of 1.73 μm, a maximum detectivity of 8.73 × 10^(10) cm·Hz^(1/2)/W, and a minimum dark current density of 1.02 × 10^(-5) A/cm^(2).Additionally, a maximum quantum efficiency of 60.3% was achieved. Subsequent optimization of fabrication enabled the realization of a 320 × 256 focal plane array that exhibited satisfactory imaging results. Remarkably, the GaSb planar detectors demonstrated potential in low-cost short wavelength infrared imaging, without requiring material epitaxy or deposition.

基于分形维数的高速铁路地震预警系统地震P波震相识别方法

为更好保障高速铁路的运营安全,高速铁路地震预警系统的实施十分必要。5级以下的小震事件占据地震事件的95%以上,提高高速铁路预警系统在小震震相识别的速度与精度能有效保障高铁安全运营。提出一种基于分形维数的地震震相识别算法,优化传统分形维数的计算方法,提高分形维数的计算速度。引入分形斜率曲线并划分为4个阶段,分析临界点的分形斜率特征,通过识别分形斜率极值时刻判断地震波精准到达时刻。提出的算法平均误差达到0.006 3 s,标准差达到0.043 8 s,满足高速铁路地震预警系统的时效性和准确度要求。