Journals >Journal of Infrared and Millimeter Waves
Contents
2005
Volume: 24 Issue 1
18 Article(s)
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Research Article
FERROELECTRIC POLARONIN LAYERED PEROVSKITE FERROELECTRIC THIN FILMS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
High quality SrBi2Ta2O9(SBT) ferroelectric thin films were fabricated on platinized silicon substrate by PLD.Electronic transport properties of SrBi2Ta2O9 ferroelectric thin films in temperaturerange of 10 to 300K were studied. The conduction mechanisms in the thin films wereanalyzed. The results indicate the existenceHigh quality SrBi2Ta2O9(SBT) ferroelectric thin films were fabricated on platinized silicon substrate by PLD.Electronic transport properties of SrBi2Ta2O9 ferroelectric thin films in temperaturerange of 10 to 300K were studied. The conduction mechanisms in the thin films wereanalyzed. The results indicate the existence of two conduction mechanisms in SBTferroelectric thin films. Due to the SBT layered structure, the carrier transport can bedivided into two parts: internal transport, which is between the (Bi2O2)2+ layers, andexternal transport, which is across the (Bi2O2)2 + layers. Especially, behavior ofelectric transport of the polaron as an internal transport carrier is first observed inthe SrBi2Ta2O9 ferroelectric thin films. Activation energy of the internal transportcarriers is Ea ～ 0.0556 eV. The results can be helpful in understanding the low DC leakage in SBT films atroom temperature..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 1, 1 (2005)
DIFFUSION COEFFICIENT OF As IN HgCdTe EPILAYERS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The diffusion coefficient of As in MBE HgCdTe epilayers was studied by using secondary ion mass spectroscopy (SIMS). The diffusion was investigated at various temperatures of 240℃,380℃,and 440℃. It was found that the partial pressure of Hg could influence As diffusion and Hg vacancies in epilayers assisted fast diffusiThe diffusion coefficient of As in MBE HgCdTe epilayers was studied by using secondary ion mass spectroscopy (SIMS). The diffusion was investigated at various temperatures of 240℃,380℃,and 440℃. It was found that the partial pressure of Hg could influence As diffusion and Hg vacancies in epilayers assisted fast diffusion of As. The As diffusion at a lower temperature of 240℃/24～48 hrs was negligibly slow. At a higher temperature of 440℃/30 min, the diffusion was obviously fast, which can cause the steep PN junction to become graded. By considering electrical activation of As acceptors and diffusion problem during annealing, an annealing condition of 440℃/30 min was found to be optimal..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 7 (2005)
STUDY ON THE JUNCTIONS OF SWIR HgCdTe PHOTO DIODES AT ROOM TEMPERATURE WITH LASER BEAM INDUCED CURRENT
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Short wavelength infrared (SWIR) focal plane arrays (FPAs) working at room temperature have many important military and cosmonautic applications. The dimensions of detectors in FPAs have gradually been reduced. Then the problem of the increase of effective optically sensitive area in photovoltaic detectors by conventioShort wavelength infrared (SWIR) focal plane arrays (FPAs) working at room temperature have many important military and cosmonautic applications. The dimensions of detectors in FPAs have gradually been reduced. Then the problem of the increase of effective optically sensitive area in photovoltaic detectors by conventional technology has been more thought of. The response of n-on-p HgCdTe photodiodes at 300K was measured by laser beam induced current(LBIC). From the results, we may see that the increase of effective optically sensitive area does exit, and the lateral diffusion of carriers to the junction periphery is the main reason..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 11 (2005)
METHOD FOR IMPROVING CLASSIFICATION PERFORMANCE OF NEURAL NETWORK BASED ON FUZZY INPUT AND NETWORK INVERSION
[in Chinese], and [in Chinese]
In order to effectively improve the classification performance of neural network, first architecture of fuzzy neural network with fuzzy input was proposed. Next a cost function of fuzzy outputs and non-fuzzy targets was defined. Then a learning algorithm from the cost function for adjusting weights was derived. And theIn order to effectively improve the classification performance of neural network, first architecture of fuzzy neural network with fuzzy input was proposed. Next a cost function of fuzzy outputs and non-fuzzy targets was defined. Then a learning algorithm from the cost function for adjusting weights was derived. And then the fuzzy neural network was inversed and fuzzified inversion algorithm was proposed. Finally, computer simulations on real-world pattern classification problems examine the effectives of the proposed approach. The experiment results show that the proposed approach has the merits of high learning efficiency, high classification accuracy and high generalization capability..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 15 (2005)
SCAN TRACK OF SYSTEM USING 45° MIRROR AND ITS EFFECT ON THE CORRECTION OF IMAGE ROTATION
[in Chinese], and [in Chinese]
The scan law of system using 45° mirror and its effect on correction of Image rotation was analyzed. The result of the correction of image rotation by software on ground was illustrated. After concerning the radius of the earth and the off-axial and mounting angel of the detector, it turns out that the system can The scan law of system using 45° mirror and its effect on correction of Image rotation was analyzed. The result of the correction of image rotation by software on ground was illustrated. After concerning the radius of the earth and the off-axial and mounting angel of the detector, it turns out that the system can acquire thorough ground information when increasing scanning angle, and the image rotation does not influence the space resolution and the band match of the system ,and image rotation can be corrected by software..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 19 (2005)
CRYSTAL STRUCTURE, SURFACE MORPHOLOGY,DEPTH PROFILE OF ELEMENTS AND MID-INFRARED OPTICAL CONSTANTS OF TE-RICH LEAD TELLURIDE FILMS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The characterizations of Te-rich PbTe layer thermal-evaporated from an excess of Te (<1 mol.%) evaporable materials were reported. The results reveal that the films obtained are polycrystalline and have single-phase NaCl-type PbTe crystal structure. It is also demonstrated that the films have homogeneous surface morThe characterizations of Te-rich PbTe layer thermal-evaporated from an excess of Te (<1 mol.%) evaporable materials were reported. The results reveal that the films obtained are polycrystalline and have single-phase NaCl-type PbTe crystal structure. It is also demonstrated that the films have homogeneous surface morphology and homogeneous distribution of Te-rich components along the layer in the range of 170 nm. The study on mid-infrared optical constants of film surface-polished indicates that the influence of surface scattering on optical properties is very small..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 23 (2005)
EXPERIMENT ON THE INFLUENCE OF DIELECTRIC LOADING ON TRANSMISSION PROPERTIES OF FREQUENCY SELECTIVE SURFACES
[in Chinese], [in Chinese], and [in Chinese]
Effects of the dielectric loading on the transmission properties of frequency selective surfaces(FSS) were preliminarily explored by experiment, especially in the thickness, loading patterns of the dielectric and the sensitivities of the forementioned parameters to the varying angle of incidence. The experimental resulEffects of the dielectric loading on the transmission properties of frequency selective surfaces(FSS) were preliminarily explored by experiment, especially in the thickness, loading patterns of the dielectric and the sensitivities of the forementioned parameters to the varying angle of incidence. The experimental results show that the resonant frequency of FSS decreases with the dielectric loading, the transmission ratio and resonant frequency are changed with the different dielectric thickness, and the dielectric symmetrically loading can stabilize the FSS transmission characteristic as the angle of incidence is varied..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 27 (2005)
MEASUREMENT OF THE ELECTRIC-OPTIC INDEX OF THIN FILMS BY USING MODULATED ELLIPSOMETRY
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The electro-optic index of PLZT thin films was measured by means of modulated ellipsometry. First the refractive index (n) and thickness (d) were measured by reflecting ellipsometry method. Then the electric field was applied on the film, and the change of refraction (δn) by was obtained by transmission ellipsometry meThe electro-optic index of PLZT thin films was measured by means of modulated ellipsometry. First the refractive index (n) and thickness (d) were measured by reflecting ellipsometry method. Then the electric field was applied on the film, and the change of refraction (δn) by was obtained by transmission ellipsometry method. Finally, the electro-optic index was calculated by the data of n, d, E and δn. This instrument has high sensitivity. So it is suitable to measure the electro-optical property of the thin film..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 31 (2005)
CONTROLLABLE REMOTE SENSING IMAGE FUSION METHOD BASED ON WAVELET TRANSFORM
[in Chinese], [in Chinese], and [in Chinese]
Spectral characteristics preservation and high spatial resolution retention are two key issues in image fusion. Different applications may require different balances between the two issues. A new controllable remote sensing image fusion method based on wavelet transform was proposed. At first, the two images were decomSpectral characteristics preservation and high spatial resolution retention are two key issues in image fusion. Different applications may require different balances between the two issues. A new controllable remote sensing image fusion method based on wavelet transform was proposed. At first, the two images were decomposed into sub-images with wavelet transform. Secondly, these sub-images were fused in wavelet space based on their characteristics. Lastly, a fused image was achieved by inverse wavelet transform. By introducing the parameters, the balance between spectral characteristics preservation and high spatial resolution retention can be achieved at different levels. With some combination of the parameters, the visual effects and the statistical parameters indicate that the fused result is slightly better than, or comparable to, those of the commonly used image fusion methods..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 34 (2005)
STUDY ON IMPROVING IMAGE SPATIAL RESOLUTION OF OPTICAL INSTRUMENTS WITH LINEAR SENSORS IN THREE-AXIS BODY-STABILIZED PLATFORM
[in Chinese], [in Chinese], and [in Chinese]
The method of improving image spatial resolution of the optical instruments with linear sensors in the three-axis body-stabilized platform was proposed by changing the sensors' relative positions as well as increasing the over-sampling ratio in some degrees. The basic iterative algorithm and the error spreading indThe method of improving image spatial resolution of the optical instruments with linear sensors in the three-axis body-stabilized platform was proposed by changing the sensors' relative positions as well as increasing the over-sampling ratio in some degrees. The basic iterative algorithm and the error spreading induced by the method were quantitively analyzed, and the certain relationship between the image spatial resolution and the image SNR was also presented. The technological feasibility of the method was proved by the patent technology of SPOT-5 HRG. This technology can been applied in the polar-stationary satellite platform under the current conditions..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 39 (2005)
ANALYSIS ON STRESS-INDUCING BIREFRINGENCE OF "PSEUDO-RECTANGLE" POLARIZATION-MAINTAINING OPTICAL FIBER
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The stress-inducing birefringence of the “pseudo-rectangle” polarization-maintaining optical fiber (PMF) was analyzed by finite element method, and its stress distributions curve and stress birefringence distributions were presented. This fiber's polarization modes, transmitting constants and modal birefringence weThe stress-inducing birefringence of the “pseudo-rectangle” polarization-maintaining optical fiber (PMF) was analyzed by finite element method, and its stress distributions curve and stress birefringence distributions were presented. This fiber's polarization modes, transmitting constants and modal birefringence were computed by the full vector finite element method. The stress and modal birefringence is about 3.33×10 -4 and 3.72×10 -4 in simulation conditions, respectively. The results of computation demonstrate that the “pseudo-rectangle” polarization-maintaining optical fiber has a number of obvious advantages with comparisons of the panda shaped fiber or the bow-tie shaped fiber: it is better in the stress transmitting effect, more uniform in the stress field distribution in fiber core and bigger in the stress-inducing birefringence..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 45 (2005)
THERMAL EMISSION CHARACTERISTICS OF AN ANISOTROPIC SCATTERING MEDIUM LAYER WITH GRADIENT INDEX
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By combined the Monte Carlo method and curved ray tracing technique, the thermal emission characteristics of an anisotropic scattering semitransparent medium with gradient refractive index was analyzed. The semitransparent and specular emerging surface of the medium layer was parallel to an opaque and diffuse substrateBy combined the Monte Carlo method and curved ray tracing technique, the thermal emission characteristics of an anisotropic scattering semitransparent medium with gradient refractive index was analyzed. The semitransparent and specular emerging surface of the medium layer was parallel to an opaque and diffuse substrate wall. The influence of the scattering albedo and scattering phase function to the apparent emittance was investigated. The results show that the influence of the scattering to the apparent emission characteristics is important. In the medium with linear refractive index distribution, when strong scattering happens, the apparent emission will reduce with the increasing of the optical thickness of the medium. This phenomenon is quite different from that in conventional semitransparent bodys..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 49 (2005)
SOI波导弯曲损耗改善方法的研究RESEARCH ON IMPROVED METHODS OF REDUCTION OF BEND LOSS OF SILICON-ON-INSULATOR WAVEGUIDES
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Improved methods of reduction of bend loss of silicon-on-insulator waveguides were simulated and analyzed by means of effective index method (EIM) and two dimensional beam propagation method (2D-BPM). The simulation results indicate that two different methods, one of which are introducing an offset at the junction of tImproved methods of reduction of bend loss of silicon-on-insulator waveguides were simulated and analyzed by means of effective index method (EIM) and two dimensional beam propagation method (2D-BPM). The simulation results indicate that two different methods, one of which are introducing an offset at the junction of two waveguides and the other is etching groove at the outside of bend waveguide, can decrease bend loss. And the later one is more effective. Meanwhile, experiments validate them. By etching groove, the insertion loss of bend waveguide of R=16mm, transverse displacement 70μm was decreased 5dB. And its bend loss was almost eliminated..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 53 (2005)
CHARACTERS FOR OPTICAL FILTER OF REMOVING BRIGHT-BACKGROUND BASED ON BACTERIORHODOPSIN FILM
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Special property of complementary suppression modulated transmission (CSMT) of bacteriorhodopsin (bR) film was used to establish a new kind of optical filter,which can be used to remove incoherent bright-background in optical image. This new kind of optical filter was demonstrated and its behavior was analyzed theoretiSpecial property of complementary suppression modulated transmission (CSMT) of bacteriorhodopsin (bR) film was used to establish a new kind of optical filter,which can be used to remove incoherent bright-background in optical image. This new kind of optical filter was demonstrated and its behavior was analyzed theoretically. The calculated results showed that the quality (the contrast, the transmitted intensity and the space distribution) of the processed image was affected by the parameters (concentration and lifetime of M state) of bR film and the intensity of the bias light. With the increasing of bR film concentration, the transmitted intensity and the curvature degree of the space distribution of the transmitted intensity decreased, and the contrast increased to the maximum and then decreased to zero. By prolonging the lifetime of M state, the transmitted intensity, the curvature degree of the space distribution of the transmitted intensity increased and the contrast increased to the stable value. Accompanying the increase of the intensity of the bias light, the transmitted intensity decreased,the space distribution was not changed, and the contrast can be increased to 1. Butwhen the concentration of bR film, the lifetime ofM state and the intensity of the bias lightwere too large, the p rocessed image might be distorted..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 56 (2005)
980nm HIGH POWER BOTTOM EMITTING VCSELS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The structure design and fabrication process of 980nm high power vertical-cavity surface-emitting laser diodes (VCSELs) were reported. The threshold current, output power and spectrum characteristics were investigated. An optical output power as high as 1.42W for a 400μm diameter device was achieved at room temperatureThe structure design and fabrication process of 980nm high power vertical-cavity surface-emitting laser diodes (VCSELs) were reported. The threshold current, output power and spectrum characteristics were investigated. An optical output power as high as 1.42W for a 400μm diameter device was achieved at room temperature. To our knowledge, this is the highest record for a single device up to now. The dependence of the CW emitting wavelength and FWHM of spectrum of a 600μm diameter device on injection current indicated the heating effects in the active region. The output power performance was further characterized by using pulse operation with pulse width from 50~1000μs..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 61 (2005)
EXPERIMENTAL AND NUMERICAL SIMULATION ON FOUR-PORT GaAlAs/GaAs PLANAR WAVEGUIDE FILTERS WITH RING RESONATOR
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the theory of four-port resonant filters, the characteristics of filters with ring resonators were numerically simulated by using two-dimensional FDTD method. The relationship between the coupling length of MMI and the filtering features was also simulated . Two narrow-band filters with ring resonators based oBased on the theory of four-port resonant filters, the characteristics of filters with ring resonators were numerically simulated by using two-dimensional FDTD method. The relationship between the coupling length of MMI and the filtering features was also simulated . Two narrow-band filters with ring resonators based on GaAlAs/GaAs planar waveguide were designed and fabricated. The measurement on filtering feature was carried out. It coincides well with that from the numeric computation..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 65 (2005)
DESIGN INFRASTRUCTURE OF SECURITY SYSTEM IN MEDICAL INFORMATION
[in Chinese], and [in Chinese]
Basing on PKI and obeying the criterion of hospital management and workflow patterns, certificate authority system and digital signature manage system were designed. The interface of CA and DSMS integrating with various hospital information systems ( such as RIS,HIS and PACS) was realized and the security verification Basing on PKI and obeying the criterion of hospital management and workflow patterns, certificate authority system and digital signature manage system were designed. The interface of CA and DSMS integrating with various hospital information systems ( such as RIS,HIS and PACS) was realized and the security verification of system information was completed. Thus, the integrity, authorization and authentication of digital medical information being used in hospitals, were ensured..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 71 (2005)
DENSE-MOVING TARGET DETECTION OF LFMCW RADAR
[in Chinese], and [in Chinese]
The received signal from target of linear frequency-modulated continues wave (LFMCW) radar is a linear frequency-modulated (LFM) signal. It is a complex problem to obtain the velocity and range of the target by estimating the parameters of LFM signal. A novel method was pressented to detect the dense-moving target baseThe received signal from target of linear frequency-modulated continues wave (LFMCW) radar is a linear frequency-modulated (LFM) signal. It is a complex problem to obtain the velocity and range of the target by estimating the parameters of LFM signal. A novel method was pressented to detect the dense-moving target based on motion compensation and “CLEAN” technique. The method avoids estimating the parameters of LFM and eliminates the different effects produced by Doppler Effect. Simulation illustrates that the proposed method can not only overcome the difficult in dense-moving target detection but also reduce 10dB detection threshold..
Journal of Infrared and Millimeter Waves
- Publication Date: Feb. 01, 2005
- Vol. 24, Issue 1, 76 (2005)
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