• Volume 31,Issue 3,2012 Table of Contents
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    • >Infrared Materials and Devices
    • Influences of Zn and Mn ions co-dopants on the optical and ferroelectric properties of BaTiO3 thin films

      2012, 31(3):193-196.

      Abstract (3485) HTML (192) PDF 1.36 M (3476) Comment (0) Favorites

      Abstract:ZnMn codoped BaTiO3 films were fabricated on Si (100) and LNO/Si (100) substrates by a solgel procedure. In order to study the effects of different doping levels on the microstructure and ferroelectric phase of BaTiO3 thin films, BTO films doped with Zn and Mn, respectively, were also investigated. Both the characterization of Xray diffraction (XRD) and atomic force microscope (AFM) indicate uniform and dense films with average grain size under 30 nm. By comparisons of the optical constant refractive index and extinction coefficient of BaTiO3 films in the wavelength from 400 nm to 700 nm, it was obtained that there is a change in the optical band gap due to the different amount of Zn and Mn added. Furthermore, a better defined PE loop with a remnant polarization of 11.26 μC/cm2 shows that Zn and Mn dopanting play an essential role in ferroelectric improvement.

    • >Terahertz and Millimeter Wave Technology
    • Design of a T-shaped terahertz imager

      2012, 31(3):197-202.

      Abstract (3045) HTML (157) PDF 1.75 M (2231) Comment (0) Favorites

      Abstract:To achieve relatively high frame rates with relatively low costs, a Tshaped terahertz imaging system with beamscanning function is presented. The system employs two orthogonally oriented copolarized scanning fanbeam antennas arranged in a Tshaped configuration. Both transmitting and receiving antennas consist of a pyramid horn feed, a fixed elliptical mainreflector to generate thin fan beam, and a rotating subreflector to realize beam scanning function, all of which are embedded between two parallel metal plates. In this paper, specific design details of such a system were discussed, especially for the systematic method proposed to design a fanbeam scanning antenna with high performance. In addition, some experimental imaging results were shown, which demonstrated the capability of the system.

    • >Remote Sensing Technology and Application
    • Accurate atmospheric transmittance model for O2 absorption band near 762 nm

      2012, 31(3):203-209.

      Abstract (2442) HTML (181) PDF 1.91 M (2106) Comment (0) Favorites

      Abstract:An atmospheric transmittance model for molecular oxygen absorption band near 762 nm is expressed by a polynomial including temperature and pressure. The polynomial coefficients are expressed as another power series of cosine of incident angle. Similarly, a mean atmospheric transmittance model is also given. Numerical tests indicate that under vast majority of circumstances the fitting errors (RMS) of the atmospheric transmittance model and those of the mean atmospheric transmittance model are less than 0.0001 and 0.0005, and their maximal errors are less than 0.0005 and 0.003, respectively. Both models were applied to the study on remote sounding of atmospheric pressure profile from space. In addition, a correction method is given for the interval error of atmospheric transmittance.

    • >Infrared Photoelectric Technology and Application
    • Thermal effect on oddsymmetric phase mask in wavefrontcoded athermalized infrared imaging systems

      2012, 31(3):210-215.

      Abstract (3079) HTML (187) PDF 1.84 M (2263) Comment (0) Favorites

      Abstract:Thermal effect on phase masks in wavefrontcoded athermalized imaging systems is analyzed. Several wellknown oddsymmetric phase functions at different temperature are derived. The properties of phase functions suffering from thermal effect are presented. The performances of the phase functions are evaluated with and without considering thermal effect by numerical simulation. The results show that the similarity of outoffocus MTFs and recoverability of blurred encoding images of the wavefrontcoded athermalized system are degraded severely by the thermal effect.

    • The carrier transportation of photoconductive HgCdTe detector irradiated by CW bandoff laser

      2012, 31(3):216-222.

      Abstract (2477) HTML (196) PDF 1.85 M (1961) Comment (0) Favorites

      Abstract:The response of photoconductive HgCdTe detectors to the irradiation of CW bandoff laser was studied. It was found that there is a point of inflexion, T0, on the temperature dependence of the voltage response of the detector. The voltage response increases with temperature for temperature of the detector T<T0, and decreases with temperature for T>T0. Two time scales are found to be due to the two thermally resistive bonding layers. The inflection temperature is determined by the impurity concentration. For temperature T<T0, the temperature dependence of the voltage response depends on the variation of mobility of the carrier , whereas T>T0, thermally generated carriers contribute to the voltage response.

    • >Infrared Materials and Devices
    • Scanning tunneling spectra for the etched surface of ptype HgCdTe

      2012, 31(3):222-225.

      Abstract (2377) HTML (168) PDF 1.51 M (1964) Comment (0) Favorites

      Abstract:Ultrahigh vacuum scanning tunneling microscopy(STM) and spectroscopy (STS)were used to characterize Hg1-xCdxTe grown by liquidphase epitaxy (LPE) method. The sample was etched with 3% Brominemethanol in 2.5 minutes. The STM images display submicrometersized pit structures with depths ranging from a few tens to a few hundreds nanometers. The scanning tunneling spectra show a larger apparent gap than the energy band gap of the bulk material due to the tipinduced band bending effect. In contrast, the scanning tunneling spectra of the pits show a finite slope through zero volt, implying the contribution of high density of band gap states which blur out the band gap information.

    • >Infrared Photoelectric Technology and Application
    • Optimization of waveguide structure for high power 1060 nm diode laser

      2012, 31(3):226-230.

      Abstract (4065) HTML (167) PDF 1.53 M (2463) Comment (0) Favorites

      Abstract:The imperfects in the wafer structure of high power 1060 nm diode laser, which prevents the improvement of laser power, was analyzed. Base on the analyzing results, the quantum well and the waveguide form were optimized. The relationship between waveguide width and laser power was simulated. According to the distribution of various modes, the position of quantum well was optimized and an asymmetric wide waveguide structure was designed. The calculation results of confinement factor for various modes show that the optimized asymmetric waveguide structure could increase the loss of high order modes while decrease the confinement factor of fundamental mode.

    • >Infrared Materials and Devices
    • The effect of Ga/N codoping on electronic structure of InSb

      2012, 31(3):231-234.

      Abstract (2690) HTML (151) PDF 1.22 M (3321) Comment (0) Favorites

      Abstract:The electronic structure and properties of zinc blende InSb codoped with Ga and N have been investigated by means of the density functional theory based on firstprinciples pseudo potential calculations. It is found that single species of N or Ga doping has a small effect on the band gap of InSb. With Ga and N codoped into InSb, its band gap is changed remarkably with the increase of codoping level of Ga/N.

    • The noise of the extended wavelength InGaAs FPA with large perimeterarearatio

      2012, 31(3):235-238.

      Abstract (2343) HTML (131) PDF 1.08 M (1932) Comment (0) Favorites

      Abstract:The total noises of focal plane array sensors, readout circuit and their coupling noise were theoretically analyzed. The temperature and integral time dependence of the noise were measured and analyzed for large perimeterarearatio of extended wavelength InGaAs FPA (38×500 μm2). The experimental results show that in certain conditions, FPA noise is not proportional to the square root of integral time. The relationship between FPA noise and dark current at different temperature were studied. Results show that the noises mainly come from 1/f noise and the current noise at the input stage of readout circuit.

    • >Other Applications
    • Kinetics of the spectral lines of high vibration state in DF/HF Lasers

      2012, 31(3):239-242.

      Abstract (1956) HTML (133) PDF 1.71 M (2292) Comment (0) Favorites

      Abstract:Unusual spectral lines of the 43 vibration state transitions of DF molecules and the 32 vibration state transitions of HF molecules have been observed in the DF/HF lasers operated with cold pumping reaction. Several typical spectrums were given, and the gain coefficients of these fundamental spectral lines of the high vibration state were calculated. Experimental results and theoretical calculations have shown that the kinetics process of these lines can not be explained by the cold pumping reaction only. The fluorine atom recombination and hot pumping reaction subsequently may be the main factors. The influences of hot pumping reaction and chain pumping reaction on the emission spectrum, gain and gain zone length of DF/HF lasers operated with the cold pumping reaction were discussed.

    • >Infrared Photoelectric Technology and Application
    • A timetodigital converter used in photon-counting LIDAR

      2012, 31(3):243-247.

      Abstract (2818) HTML (192) PDF 1.61 M (5031) Comment (0) Favorites

      Abstract:Timing system was used to measure the timeofflight(TOF) of laser pulse in light detection and ranging(LIDAR). Performance of a LIDAR system is directly influenced by the properties of the timing system. A timetodigital converter(TDC) based on FPGA was designed for photoncounting LIDAR. By integrating the delay line interpolation into FPGA, the designed TDC could measure the TOF with fine accuracy and resolution. The performance of the TDC and its application in photoncounting LIDAR were analyzed and studied experimentally. Eventtiming of 9 channels was implemented with this TDC, with a resolution of 29 ps and a timingaccuracy of 37 ps. Using a LIDAR system equipped with the TDC, threedimensional imaging can be realized with time accuracy of 421 ps and 6.3 cm resolution in space.

    • >Infrared Spectroscopy and Spectral Analysis
    • Evaluation of erythropoietin efficacy on diabetic retinopathy based on molecular hyperspectral imaging (MHSI) system

      2012, 31(3):248-253.

      Abstract (2407) HTML (186) PDF 2.24 M (1807) Comment (0) Favorites

      Abstract:Integrate imaging technology, spectrum technology and microscope, a novel molecular hyperspectral imaging (MHSI) system based on AOTF (acoustooptic tunable filters) was presented. The system was used to capture hyperspectral images of rat retinal sections selected from three groups: normal(N), diabetic(D), and EPOtreated(E0). By processing hyperspectral images data of 30 samples, single band images and the pseudocolor images of N、D、E0 group are gained. Typical spectra curves of the ONL cells of N、D、E0 are extracted. By analyzing these images, descending order of the ONL thickness is N、E0、D. The experimental results cite that the ONL thickness of E0 group will be increased after EPO treated. By analyzing these spectrums, transmission intensity of D group is generally higher than that of N group in the spectral field from 550 nm to 1000nm and transmission intensity of E0 group is in the middle of D and N. By analyzing spectrum relations, results show the spectral signature of the E0 group was more similar to that of N than that of D to N. The above results suggest EPO may prevent cell apoptosis and has protective effect on rat DR at a certain level. MHSI system may probably provide a potential approach to researching pathogenesis、causes of blindness and drug efficacy of DR in future.

    • >Infrared Photoelectric Technology and Application
    • Magnetic modulation of magneticfluid based on the symmetrical metalcladding optical waveguide

      2012, 31(3):254-257.

      Abstract (2346) HTML (159) PDF 1.34 M (2402) Comment (0) Favorites

      Abstract:A new type of symmetrical metalcladding optical waveguide structures is proposed. The guiding layer that supports the oscillating field is submillimeter scale and severs as the sample room. The waterbased Fe3O4 magnetic fluid with a volume fraction of 0.15% is injected into the sample room. The ultrahigh order modes are excited by a 860 nm laser beam on the structure with small incident angle (<5). Owing to the strong concentration of the magnetic field, the sensitivity of the ultrahighorder modes is very high. The rise and fall time of magnetic fluid is 2 ms when 10 mT magnetic field is applied.

    • >Terahertz and Millimeter Wave Technology
    • Moving target detection and location based on millimeterwave InISAR imaging

      2012, 31(3):258-264.

      Abstract (2749) HTML (163) PDF 2.42 M (1632) Comment (0) Favorites

      Abstract:An inverse synthetic aperture radar (ISAR) imaging method based on motion compensation of a moving target was presented. The concept of radar imaging was applied to the process of moving target detection with low signal to noise ratio(SNR). The lateral and radial velocity of the target can be acquired by means of imaging processing. The location of the moving target and estimation of its crosssectional area could be fulfilled using the multibaseline image interferometric method. The geometric model for imaging moving target was established. A method for the compensation of signals from channels of multi antenna time division multiplexing (TDM) receiver was proposed. The unambiguous angle orientation based on multibaseline phase unwrapping was presented. The influence of the image SNR on interferometric orientation accuracy was analyzed. The validity of the proposed method was testified by both simulation and an example of its application.

    • >Image Processing and Software Simulation
    • Cayley-Menger determinantbased endmember extraction algorithm for hyperspectral unmixing

      2012, 31(3):265-270.

      Abstract (2537) HTML (152) PDF 2.20 M (1886) Comment (0) Favorites

      Abstract:A fast CayleyMenger determinantbased endmember extraction algorithm for hyperspectral unmixing was proposed. The algorithm is to find the simplex enclosing the hyperspectral data with minimum volume. It improves current simplexbased algorithms in several aspects. The introduction of CayleyMenger determinant makes it easy to use features of Hermite matrix to accelerate the searching process and gives a stable result finally. Moreover, a dimensionality reduction transform is not necessary in this algorithm, which will avoid the loss of useful information during the dimensionality reduction. The experimental results on synthetic and real hyperspectral dataset demonstrated that the proposed algorithm is a fast and accurate algorithm for the hyperspectral unmixing.

    • Block adjustment of InSAR images based on the combination of F.Leberl and interferometric models

      2012, 31(3):271-276.

      Abstract (2508) HTML (142) PDF 2.15 M (2568) Comment (0) Favorites

      Abstract:为解决西部测图中缺少控制点的问题,提出了一种新的干涉合成孔径雷达(InSAR)影像区域网平差方法.该方法将F.Leberl模型与干涉测量模型相结合,并采用交替趋近与LDL’稀疏矩阵分解技术求解大规模法方程.实验结果表明,与传统的基于F.Leberl模型的平差方法相比较,提出的方法精度更高.由于新模型中增加了三个定标参数,因此能够同时实现多航带幅度图像以及数字高程模型(DEM)的联合平差.最后结合实际机载InSAR系统参数对影响平差精度的因素进行了详细的分析.

    • >Infrared Spectroscopy and Spectral Analysis
    • VISNIR reflectance spectroscopy of the organic matter in several types of soils

      2012, 31(3):277-282.

      Abstract (3261) HTML (147) PDF 2.34 M (2568) Comment (0) Favorites

      Abstract:Estimating the content of soil organic matter (SOM) using hyperspectral remote sensing is an inevitable requirement for precision agriculture. In this study, averages of spectral reflectance and first derivative of 791 sample pieces were measured in the visible and nearinfrared (350~2500 nm) bands, which belong to five different soil types from four provinces, including phaeozem in Heilongjiang, alluvial soil in Henan, paddy soil in Sichuan and Zhejiang, purple soil in Sichuan and Zhejiang, and seashore saline soil in Zhejiang. The correlation coefficients between organic matter content and spectral reflectance were calculated, while the characteristic spectral bands mentioned in precedent researches were summarized. The results show that 600~800nm can be used as common characteristic bands of these different types of soils from different regions in the study, which is important for building the universal model for soil organic matter with alternative parameters. Another conclusion is that above 2% in SOM is not necessary for predicting SOM.

    • >Image Processing and Software Simulation
    • Soil moisture retrieval based on GABP neural networks algorithm

      2012, 31(3):283-288.

      Abstract (2894) HTML (198) PDF 2.29 M (3419) Comment (0) Favorites

      Abstract:active andA new semiempirical model is presented for soil moisture content retrieval, using ENVISAT ASAR and LANDSATTM data collaboratively. Firstly, a back propagation(BP) neural network algorithm(GA) is introduced, and a genetic algorithm is applied to optimize the weights of the node of BP neural network. Then the TM bands (TM3, TM4, TM6) and ASAR data(VV, VH, VH/VV) are taken as the input of the GABP neural network, and the output corresponds to the ground soil moisture. The partial field measurements of soil moisture are used as training samples to train the network and to achieve the map of soil moisture distribution. The field measurements are used to test the validity of the BP neural network algorithm and effectiveness of the active and passive remote sensing cooperative inversion. The comparison between the inversion using single data set(TM or ASAR), and the cooperative inversion of active and passive remote sensing data demonstrates that the new algorithm is more effective, and shows considerable potential in soil moisture retrieval by integrating active and passive remote sensing data. passive remote sensing; GABP neural network; soil moisture; inversion

Editor in chief:Jun-Hao CHU

International standard number:ISSN 1001-9014

Unified domestic issue:CN 31-1577

Domestic postal code:4-335

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