Abstract:Relaxor ferroelectric 0.74Pb (Mg1/3Nb2/3)O3-0.26PbTiO3thin films were prepared on LaNiO3-buffered silicon substrates by radio-frequency magnetron sputtering. The effect of deposition temperature on films" microstructures and optical properties was investigated. The sample deposited at 500℃ exhibits not only a pure perovskite phase, highly (110)-preferred orientation, and dense and crack-free morphology, but also the largest average remnant polarization of 17.2 μC/cm2 among all investigated films. With Cauchy model the refractive indices and extinction coefficients for these specimens have been obtained by fitting experimental reflectance spectra. At a wavelength of 633 nm, the value of refractive index is 2.41 was obtained for the thin films deposited at 500 ℃. In addition, optical band gaps of the films are in the range of 2.97–3.22 eV. A preliminary discussion has been carried out on the difference in the optical properties of these films.

Abstract:A 75 GHz monolithic-microwave integrated-circuit (MMIC) four- fingers cascode power amplifier in InP double heterojunction bipolar transistors (DHBT) technology with an fmax about 150 GHz was reported. The amplifier has 15μm x 4μm total emitter area and exhibits a power gain of 12.3 dB at 75 GHz with 13.92 dBm output saturated power. The amplifier achieves a peak output power of 14.53 dBm with 2 dBm input power at 72.5 GHz. The MMIC adopts coplanar waveguide (CPW) structure as the transmission line structure with area of 1.06 mm x 0.75 mm .

Abstract:In this paper we present the results of positron annihilation doppler broadening spectroscopy (PADB), X-ray diffraction spectra (XRD), and atomic force microscopy (AFM) measurements on the undoped GaSb and Te-doped GaSb films grown on GaAs substrate by molecular beam epitaxy(MBE). Research shows that the S parameter is smaller in GaSb film than the bulk material. The defects in the Te-doped N-type semiconductor GaSb obtained by MBE are mainly vacancies and impurity atoms instead of complex defects 。

Abstract:The anisotropy of photocurrent induced by two-photon absorption in [110]-cut nearly-intrinsic crystal silicon sample is investigated. The anisotropy coefficient of third-order nonlinear susceptibility of Si at wavelength of 1.3 μm is measured to be -0.25, and the ratio of χxxxx to χxxyy is 2.4. The independent element χxxxx is consequently obtained to be about 1.49×10-19 m2/V2 based on the previously observed result of χxxyy.

Abstract:Plane wave expansion method is introduced to simulate the band structures of two-dimensional photonic crystals made of Archimedes A7 lattice of circular and square dielectric rod in air. The bandgaps of Archimedes A7 lattice with dielectric rods is also discussed as the refractive index, filling fraction and rotation angle change. The results show that the complete bandgap can be obtained when the refractive index is greater than 2.40, the width of complete bandgap reaches the maximum when the dielectric refractive index of the circular rod is equal to 2.60. For the Archimedes A7 lattice of square dielectric rod, the complete bandgap reaches the maximum when the dielectric refractive index equals 3.80.The maximum complete bandgap changes in a narrow range as the refractive index increases. When the rotation angle of the square dielectric rods changes, the maximum bandgaps keeps constant for a fixed refractive index.However after the change of rotation angle, the complete bandgap appears in alarge scale of the filling fraction.

Abstract:With the aid of photolithography, arrays of one-dimensional porous silicon photonic crystal with the middle infrared mid-gap (λ=5、6、7、10 μm) were fabricated successfully by the combination of microelectronic technique and the electrochemical etching method. For practical use, the roughness of the surface was improved by deposited a Si3N4 thin film with 5000 ?. Then their optical and roughness properties were characterized by FTIR and AFM, respectively. As a result of the synergetic effects rendered by heat isolation and high reflection properties, the array of the one-dimensional porous silicon photonic crystal exhibit feasibility as the substrate for pyroelectric infrared sensor.

Abstract:The determination of the cloud-top height is of importance to the study of atmospheric physics and climate. An effective method to detect cloud-top height is the stereoscopic observation.. According to several working modes of this method and their principles, the modes for analyzing errors in the cloud-top height detection is established in the single satellite mode, and specific error formulas are presented . By means of simulating satellite parameters, the error of cloud-top height detection is analyzed in different observation modes of single satellite. The results of the simulation illustrate that the three-line-array detector observation mode has relatively greater advantages than other models in detecting cloud-top height by the stereoscopic observation.

Abstract:This paper addresses the cross-calibration method of infrared window and water vapor channels of VISSR (Visible and Infrared Spin Scan Radiometer) with reference data provided by the onboard geostationary satellite FY-2E with MODIS (MoDerate Resolution Imaging Spectroradiometer) and the onboard polar-orbit satellite TERRA. The cross-calibration is implemented using the satellite remote date in May, July and December of 2010. The results show that the bright temperature calculated using cross-calibration coefficients is nearly equal to the observed value of MODIS for all collocation samples, and about 90 percent of temperature bias is less than 1K. It also can be seen that the calibration slope decreases obviously from May to the beginning of July, and ascends slightly in the last ten-day of July，then keeps steady in December. The variation of calibration coefficients reveals great consistent with that of remote temperatures. All in all, the cross-calibration method described here can increase frequency and accuracy, and provide a methodological foundation for on-orbit calibration of FY-2E.

Abstract:A method is proposed to inhibit the leakage of electromagnetic waves on the surface of 2D photonic crystals using total internal reflection. The band structures of 2D metallic photonic crystals with different background mediums are analyzed. The band structures as a function of the filling factor are obtained via FDTD method. The metallic photonic crystals are composed of Cu columns. Two kinds of background media, air and PMMA, were selected in this study. The band structures of these two 2D square-lattice metallic photonic crystals were analyzed separately. The results indicate that the metallic photonic crystals filled with PMMA have a narrower first band gap and a lower second band gap than the metallic photonic crystals filled with air. A third band gap appears in the metallic photonic crystals with PMMA as the background medium when the filling factor reaches 0.70. This work provides a good reference value for the application of photonic crystals.

Abstract:The mechanism damage to the optical coatings of filters induced by femtosecond laser at different wavelengths was studied. A near infrared wavelength tunable femtosecond laser was used to rediate the visible wavelength filter from backside. The wavelengths were selected in the transitional region of the filter pass band and the corresponding thresholds of average power density were obtained. Based on the avalanche ionization process, the relationship between damage threshold and distribution of interference field was investigated. The theoretical results can predict the trend of thresholds. The results indicate that the damage behavior of a coating irradiated by femtosecond laser pulses exhibits an overall behavior. The damage threshold decreases with the increase of transient residual energy in the multi-layer structure of the coating.

Abstract:Modified MERIS terrestrial chlorophyll Index (M-MTCI) was developed based on modifications of MTCI . M-MTCI is better than MTCI and double-peak canopy nitrogen index (DCNI) on aspects of chlorophyll content retrieval precision (when LAI >1). Besides M-MTCI has better chlorophyll and LAI effects separation than MTCI. Validation by numerical simulations and in-situ measurements shows that M-MTCI is a reliable VI for chlorophyll content retrieval. Therefore, M-MTCI is a prosperous VI for chlorophyll content monitoring applications.

Abstract:In order to develop compact, reliable and high power terahertz radiation sources, multi-mode second-harmonic operation in a terahertz gyrotron was investigated theoretically and experimentallyin . The theoretical calculation results show that there are five second-harmonic modes which operate at single-mode oscillation state in the gyrotron by adjusting the design parameters. Experimental results demonstrate that there are four second-harmonic modes (TE16, TE64, TE46 and TE26 ) in the gyrotron operating with a 1.5A/41kV electron beam. Output powers of 1.5, 2.1, 3.0 and 1.4kW can be generated at the corresponding frequencies of 0.391THz, 0.404THz, 0.416THz and 0.423THz, respectively.

Abstract:The principle and key technologies of the optic real-time signal process system for synthetic aperture microwave radiometer were analyzed. An infrared real-time signal process system prototype for an X-band synthetic aperture microwave radiometer with six elements was developed, the system tests and one dimensional imaging experiments of point source were carried out. The clear interference fringes pattern were obtained. The primary experiment results validate that feasibility of real-time signal processing for synthetic aperture microwave radiometer and the correctness of the system design.

Abstract:This paper analyzed the importance of relative radiometric normalization(RRN) in remote sensing and aerophotogrammetry filed. The linear correction method of RRN was studied. A high automatic RRN method was proposed based on scale-invariant feature transform(SIFT)。It was found that the RRN can minimized radiometric difference among images caused by inconsistencies of acquisition conditions (such as weather、season, etc) rather than in surface reflectance. Compared with the traditional ways, the new method is more robust and automatic.

Abstract:The dumb bell resonant cavities characteristics for W-band sheet beam klystron (SBK) are analyzed with one-, three-, and five-gap coupled cavity models by three dimensional high frequency simulation software(CST-MSW). The dependence of the cold parameter on the configurations of cavity was analyzed. For the particle in cell (PIC) simulation analysis, the optimized cavity frequency combination of eight-cavity WSBK circuit was obtained using 2-D software SBK2D, which runs with speed,, thereby allowing an efficient investigation of input parameters. To unify the electronic-beam wave interaction system's hot parameter design, the calculation results are examined by PIC simulation (MAGIC-3D), and show good agreement with CST, thereby confirming the design method mentioned above. These results provide key parameters and a good foundation for developing higher performance on RF structure of sheet beam klystron in the future.

Abstract:The bio-optical retrieval model of suspended particle matter concentration (Cmin) at single infrared wavelength based on the suspended particle in Tai Lake has specific mechanism. The measured data of suspended particle matter and bio-optical properties during 2006 to 2009 were used to test this bio-optical algorithm. The results indicate that the spatio-temporal variation of specific backscattering coefficient is the primary factor to the retrieval precision of suspended particle . The absorption coefficient of suspended particle in the infrared wavelength also have significant effect on the retrieval precision of suspended particle . This retrieval model can be successfully applied to the MERIS image data. The resuspended sediment will significantly increase the concentration of suspended particle in Tai lake according to the MERIS image retrieval result and wind speed monitor data in situ.

Abstract:The stimulated Raman Stokes and anti-Stokes scattering of water are studied with 532nm laser. The experimental results show that plasma of water is generated when the pump energy of laser is 4mJ. The intensity and bandwidth of the Stokes line OH stretching vibration are increased as the pump laser energies are increased from 5mJ to 15Mj, and the center wavelength of Stokes become blue-shifted. The anti-Stokes line of OH stretching vibration is generated when the pump laser energy is 15mJ. The enhancement of the stimulated Raman scattering of water cluster is well explained by the laser-induced plasma. These results show great promise for water as Raman laser media.

Abstract:Combining scattering theory and principle of SAR, a novel prediction model is proposed based on the multi-path scattering characteristics in the SAR image of cylinder tanks, for both the fixed and the floating top styles. The model can provide the relationship between the geometry parameters of the tank, the SAR parameters , the approximation position, and the scatting strength of the bright region in the SAR image. The validity of the model is proved by analyzing the Terra-SAR data and simulation experiments. Furthermore, geometry extraction is successfully implemented on the Terra-SAR data. The results show that the model is better than traditional methods in precision and stability.