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Contents
2001
Volume: 20 Issue 3
18 Article(s)
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Research Article
REFRACTIVE INDEX ENHANCEMENT EFFECT IN Hg1-xCdxTe NEAR THE FUNDAMENTAL GAP
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The refractive indices of Hg1-xCdxTe bulk samples with the composition x=0.276, 0.309, and 0.378 were measured by infrared spectroscopic ellipsometry at room temperature in the energy regions which were below, across, and above the fundamental band gap. An obvious refractive index enhancement effect was observed in theThe refractive indices of Hg1-xCdxTe bulk samples with the composition x=0.276, 0.309, and 0.378 were measured by infrared spectroscopic ellipsometry at room temperature in the energy regions which were below, across, and above the fundamental band gap. An obvious refractive index enhancement effect was observed in the refractive index spectra for each composition. The energy position of the maximal refractive index value equals approximately that of the band gap. The refractive index versus wavelength λ above the band gap for x between x=0.276 and 0.378 was modeled using a Sellmeier dispersion relationship n2(λ)=a1+a2/λ2+a3/λ4+a4／λ6..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 161 (2001)
INFLUENCE OF MS INTERFACE TRANSPORT ON THE CURRENT-VOLTAGE CHARACTERISTIC OF MCT PV DEVICE
[in Chinese], [in Chinese], and [in Chinese]
The influence of MS transport on the current-voltage characteristic of MCT PV device was investigated based on the current-voltage characteristics of MCT Schottkey barrier. The data of some devices were also discussed.The influence of MS transport on the current-voltage characteristic of MCT PV device was investigated based on the current-voltage characteristics of MCT Schottkey barrier. The data of some devices were also discussed..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 165 (2001)
ANALYSIS OF FLUORESCENT AND RAMAN SPECTRA WITH SPATIAL RESOLUTION (DEPTH ANALYSIS) METHOD
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A depth analysis spectra method for researching fluorescent and Raman spectra was developed since a self-absorption was often observed in fluorescent spectra of thick solid sample. The intensity change of self-absorption could be observed to explore the secrets of solid state spectra by depth analysis method. The RamanA depth analysis spectra method for researching fluorescent and Raman spectra was developed since a self-absorption was often observed in fluorescent spectra of thick solid sample. The intensity change of self-absorption could be observed to explore the secrets of solid state spectra by depth analysis method. The Raman and fluorescent spectra of Nd3+∶YAG crystal were measured with 633nm of HN laser and 514.5nm of Ar+ laser. Some fluorescent lines which possess self-absorption were observed, whose intensity changes with depth of confocal plane. It shows that spatial resolution (depth analysis) method is a powerful experimental means for studying solid state spectroscopy..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 169 (2001)
INDIUM DOPING ON MBE GROWN HgCdTe
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The results of indium doping on MBE grown HgCdTe were described.It was found that the indium electrical activation was close to 100% in HgCdTe and the donor activation energy was at least smaller than 0.6meV. It was confirmed that a donor concentration of ～3×1015cm-3 was necessarily preserved for infrared FPAs appThe results of indium doping on MBE grown HgCdTe were described.It was found that the indium electrical activation was close to 100% in HgCdTe and the donor activation energy was at least smaller than 0.6meV. It was confirmed that a donor concentration of ～3×1015cm-3 was necessarily preserved for infrared FPAs applications. The diffusion behavior of indium was studied by thermal annealing, and a diffusion coefficient of ～10-14cm2/sec at 400℃ was obtained, which confirms the feasibility and validity of indium as an n-type dopant..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 174 (2001)
FEMTOSECOND PHOTO-CONDUCTIVE CHARACTERISTICS OF LT-GaAs
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The ultrafast photo-conductive characteristics of LT-GaAs were studied with femtosecond photocurrent correlation measurements. A response time ranging from 350 to 390 fs of a LT-GaAs micro-coplanar-strip-lines gap for different exciting photon energies and different bias voltages was obained. It has been estimated thatThe ultrafast photo-conductive characteristics of LT-GaAs were studied with femtosecond photocurrent correlation measurements. A response time ranging from 350 to 390 fs of a LT-GaAs micro-coplanar-strip-lines gap for different exciting photon energies and different bias voltages was obained. It has been estimated that the transport rate of the photo-excited electrons in the gap is 1000cm2/V.s. The experimental traces are well consistent with a theoretical normalized transient photo-current correlation function..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 179 (2001)
LOW-TEMPERATURE RAMAN SCATTERING SPECTRA AND ELECTRICAL PROPERTIES OF Cd1-xZnxTe(x=0.04) OF DIFFERENT SURFACE TREATMENTS
[in Chinese], and [in Chinese]
Fourier transform Raman scattering spectra and current-voltage (I-V) features were measured for Cd1-xZnxTe(x=0.04) surfaces of different treatments. By analyzing the anti-stokes Raman spectra and comparing with surface current-voltage (I-V) curves, it was concluded that the behavior of the lattice phonons which are assFourier transform Raman scattering spectra and current-voltage (I-V) features were measured for Cd1-xZnxTe(x=0.04) surfaces of different treatments. By analyzing the anti-stokes Raman spectra and comparing with surface current-voltage (I-V) curves, it was concluded that the behavior of the lattice phonons which are associated with surface treatments reflects the perfection-variation of Cd1-xZnxTe(x=0.04) surface. It was also found that Te precipitates on Cd1-xZnxTe(x=0.04) surface are crucial to surface quality. In addition, potential application of the different surface treatments was discussed..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 184 (2001)
AN EFFICIENT AND ROBUST SCHEME OF IMAGE-CODING
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new wavelet-based image-coding scheme was proposed. The Variable-Coefficient Fixed-Length(VCFL) Coding method was used to code the wavelet subband coefficients of the image. The codebook was obtained from symbol probability. By a way similar to Atithmetic Coding, a bunch of symbols was mapped to the code in the codebA new wavelet-based image-coding scheme was proposed. The Variable-Coefficient Fixed-Length(VCFL) Coding method was used to code the wavelet subband coefficients of the image. The codebook was obtained from symbol probability. By a way similar to Atithmetic Coding, a bunch of symbols was mapped to the code in the codebook. Several error-concealement methods were also adopted to improve the robustness. Simulation results show that our new scheme has higher compression ratio and robustness..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 189 (2001)
3D IMAGE SEGMENT METHOD WITH FORECASTING CAPABILITY
[in Chinese], [in Chinese], and [in Chinese]
A new 3D image segmentation algorithm was proposed. This algorithm integrates the improved Active Contour model and a new forecast algorithm. The forecast algorithm is based on the peculiarity of 3D images i.e the deformation of the contour along the space or time axis is continuous in 3D images. The forecast algorithmA new 3D image segmentation algorithm was proposed. This algorithm integrates the improved Active Contour model and a new forecast algorithm. The forecast algorithm is based on the peculiarity of 3D images i.e the deformation of the contour along the space or time axis is continuous in 3D images. The forecast algorithm analyzes the trend of the deformation of the contour in the segmented images, then prognosticates the location and the shape of the contour in the next image. Experiments on medical anatomic images show that the new algorithm can observably improve the accuracy of the segmentation and reduce the time needed..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 194 (2001)
EM ALGORITHM FOR ESTIMATING THE NOISE DEVIATION OF THE IMAGE IN THE WAVELET DOMAIN
[in Chinese], [in Chinese], and [in Chinese]
A new method was proposed to estimate noisy image’s quality. This approach uses Gaussian mixture model to simulate the histogram of the highest subband’s coefficients in the wavelet domain. The parameters of this model can be calculated by EM algorithm. The smallest deviation of the Gaussian mixture model is selected aA new method was proposed to estimate noisy image’s quality. This approach uses Gaussian mixture model to simulate the histogram of the highest subband’s coefficients in the wavelet domain. The parameters of this model can be calculated by EM algorithm. The smallest deviation of the Gaussian mixture model is selected as the noise deviation. The authors' proposed method can provide better result than the other traditional ones..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 199 (2001)
ANTIREFLECTIVE AND PROTECTIVE FILMS PREPARATION ON ZnS DOME SONG Jian-Quan（College of Materials Science and
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Antireflective and protective films consisted of GexC1-x films were prepared by reactive radio frequency magnetron sputtering (RRFS) on ZnS dome. A computer was used to simulate the thickness distribution of the film of ZnS dome for different movement tracks, and the best one was got by using the best dome movement traAntireflective and protective films consisted of GexC1-x films were prepared by reactive radio frequency magnetron sputtering (RRFS) on ZnS dome. A computer was used to simulate the thickness distribution of the film of ZnS dome for different movement tracks, and the best one was got by using the best dome movement track. The thickness uniformity of films could meet the application requirement when films were deposited by RRFS on the dome. The computer control system was built according to the simulation results, and antireflective and protective films consisted of GexC1-x films were deposited on the ZnS dummy dome. The results show that 1) the variation of thickness is lower than 10%, 2) the average transmittance, in the 8～11.5μm waveband, is raised from 69.6% to above 87.2% after the films are coated on double sides, 3) the average transmittance variation is less than 1.2%. Thus the requirements of ZnS dome in infrared application are met..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 203 (2001)
IMAGE FUSION SCHEME OF PIXEL-LEVEL AND MULTI-OPERATOR FOR INFRARED AND VISIBLE LIGHT IMAGES
[in Chinese], and [in Chinese]
A novel pixel-level image fusion scheme was presented based on multiscale decompositon. First, the wavelet transform is used to perform a multiscale decomposition of each image. Then, the wavelet coefficients of fused image are constructed using multiple operators according to different fusion rules. This approach is sA novel pixel-level image fusion scheme was presented based on multiscale decompositon. First, the wavelet transform is used to perform a multiscale decomposition of each image. Then, the wavelet coefficients of fused image are constructed using multiple operators according to different fusion rules. This approach is successfully used to fuse the infrared and visible light images. The experimental results show that the fusion scheme is effective and the fused images are more suitable for human visual or machine perception..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 207 (2001)
THE ALGORITHM OF IMAGE TRANSITION REGION AND ITS IMPROVEMENT
[in Chinese], [in Chinese], and [in Chinese]
The deficiency of original image transition region theory and its origin were analyzed. Based on the directional property of neighborhood pixels in the transition region, one-dimensional linear regression process was introduced to eliminate the influence of random fluctuations in local image regions.The practical resulThe deficiency of original image transition region theory and its origin were analyzed. Based on the directional property of neighborhood pixels in the transition region, one-dimensional linear regression process was introduced to eliminate the influence of random fluctuations in local image regions.The practical results show that the robustness and the accuracy of new algorithm could be improved greatly..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 211 (2001)
PARAMETERS OPTIMIZATION OF SYNERGETIC NEURAL NETWORK
[in Chinese], [in Chinese], and [in Chinese]
An optimization algorithm based on genetic algorithm for parameters of synergetic neural network was proposed, which searched the optimal solutions in the parameters space of synergetic neural network using the globally optimal searching ability of genetic algorithm. The test upon the numeral samples from ‘Car License An optimization algorithm based on genetic algorithm for parameters of synergetic neural network was proposed, which searched the optimal solutions in the parameters space of synergetic neural network using the globally optimal searching ability of genetic algorithm. The test upon the numeral samples from ‘Car License Recognition System’ shows that the optimization algorithm is able to improve the recognition performance of synergetic neural network effectively, and make the recognition rate reach the level of real application (98.4%). Additionally, the functions of parameters of synergetic neural network in object recognition were discussed..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 215 (2001)
MULTISENSOR IMAGE FUSION BASED ON TREE-STRUCTURE WAVELET DECOMPOSITION
[in Chinese], and [in Chinese]
An algorithm for multisensor image fusion was proposed based on tree-structure wavelet decomposition. Under some special energy rules, it can adaptively implement subband decomposition and image fusion according to the image features. Experimental results of visible image and infrared image fusion, visible image and miAn algorithm for multisensor image fusion was proposed based on tree-structure wavelet decomposition. Under some special energy rules, it can adaptively implement subband decomposition and image fusion according to the image features. Experimental results of visible image and infrared image fusion, visible image and millimeter wave image fusion were given, which show the proposed method can achieve better fusion performance than the traditional pyramid wavelet decomposition..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 219 (2001)
WAVELET KERNEL FUNCTION NETWORK
[in Chinese], [in Chinese], and [in Chinese]
A new wavelet kernel function network (WKFN) was proposed as an alternative of support vector machine (SVM). Simulation experiments show that the performance of approximation and recognition of WKFN is equal to that of the corresponding SVM, but gets an advantage over that of a general neural network.A new wavelet kernel function network (WKFN) was proposed as an alternative of support vector machine (SVM). Simulation experiments show that the performance of approximation and recognition of WKFN is equal to that of the corresponding SVM, but gets an advantage over that of a general neural network..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 223 (2001)
STUDY ON HOLLOW-WAVEGUIDES OF POLYSTYRENE-COATED SILVER-GLASS FOR TRANSMISSION OF INFRARED LASER ENERGY
[in Chinese], and [in Chinese]
Polystyrene-coated hollow glass waveguides were fabricated by means of liquid phase deposition method. The length of the waveguide is about 1m and its diameter is 800 to 1200μm. The minimum optical loss of the waveguides is 1.73dB/m with damage threshold higher than 11.2W (17.2W/mm2) for CO2 laser (10.6μm). ExperimentaPolystyrene-coated hollow glass waveguides were fabricated by means of liquid phase deposition method. The length of the waveguide is about 1m and its diameter is 800 to 1200μm. The minimum optical loss of the waveguides is 1.73dB/m with damage threshold higher than 11.2W (17.2W/mm2) for CO2 laser (10.6μm). Experimental results show that polystyrene-coated silver hollow glass waveguides are suitable for delivery of CO2 laser in medical applications, and are also promising for energy transmission of other infrared lasers..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 229 (2001)
DISTRIBUTION OF EFFECTIVE TEMPERATURE IN MICRO-PHOTOLUMINESCENCE MAPPING ON CdZnTe WAFER
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Micro-photoluminescence (μ-PL) mapping with the spatial resolution of micrometer was performed on a CdZnTe(CZT) wafer to study its characteristics of the sub-micrometer layer under the surface. Two scales of mapping on micrometer over the defect-containing region and on millimeter over the large area were employed. EacMicro-photoluminescence (μ-PL) mapping with the spatial resolution of micrometer was performed on a CdZnTe(CZT) wafer to study its characteristics of the sub-micrometer layer under the surface. Two scales of mapping on micrometer over the defect-containing region and on millimeter over the large area were employed. Each acquired PL spectrum was fitted based on a physical model. Statistical results of the fitting parameters of effective temperature Te show two centers for the temperature distribution, implying two mechanisms for the PL processes. The inhomogeneity for the luminescent points was also shown by the statistics. The maps of Te directly give the temperature position of each PL points. Similar μ-PL mapping was carried out after Br polishing on the sample surface. The fitting results show a good improvement on the homogeneity of Te. The two different defects on the Te map after polishing show different behavior, suggesting different origins for them. The statistics and the map of Te in μ-PL mapping on the scale of millimeter over large area demonstrate the general properties of the CZT wafer..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 233 (2001)
DETECTION AND ANALYSIS OF WEAK TARGET WITH INFRARED IMAGE BASED ON K-L TRANSFORM
[in Chinese], [in Chinese], and [in Chinese]
In view of the characteristics of the low contrast and small dimension of targets and the complexity of background in infrared image, a method of detecting and describing infrared weak target was presented with improved K-L transform and generalized K-L transform. Thus the infrared weak target can be detected in low siIn view of the characteristics of the low contrast and small dimension of targets and the complexity of background in infrared image, a method of detecting and describing infrared weak target was presented with improved K-L transform and generalized K-L transform. Thus the infrared weak target can be detected in low signal-to-noise ratio..
Journal of Infrared and Millimeter Waves
- Publication Date: Jun. 01, 2001
- Vol. 20, Issue 3, 238 (2001)
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