Abstract:Epitaxial films of GaAs/AlGaAs multi-quantum wells were lifted-off from its grown substrate and transferred to a Si substrate,a typical infrared optical window material.The lifted-off sample was fabricated into quantum well infrared photodetector(QWIP).The responsivity and photocurrent spectrum of the lifted-off QWIP is shown in similar to that of QWIP processed from the as-grown wafer.It demonstrates that the lift-off process can be used in QWIP process without device performance degradation.The lifted-off process can provide a new possibility to integrate the QWIP devices with other optical device to enhance the detector performance.

Abstract:利用场发射扫描电子显微镜对TEA-CO2强激光脉冲辐照的Hg0.8Cd0.2Te晶片表面进行了观察,并利用电镜自带的能谱分析仪对其表面进行了成分分析.在单脉冲能量为1.91J,峰值功率密度为2.63×107W/cm2的脉冲CO2激光辐照下,晶片表面呈现出熔融迹象,且晶片表面的化学组分比发生明显的变化.理论与实验研究结果表明激光急速加热使晶体表面的Hg-Te键破坏,从而导致Hg损失,而Hg损失程度与热作用过程的时间有关.随着脉冲作用次数的增加,多脉冲的连续作用使Hg损失加剧,晶片表面成分变化更加突出.

Abstract:军事和安全应用都需要利用红外探测技术来进行目标跟踪和搜索.由于红外或热成像系统探测的目标辐射能量低,因此需要光学系统具有强的集光能力;另外,用凝视方式可以获取大场景红外图像以去除传统的机械扫描装置,这要求红外光学系统具有足够大的视场.该工作研究的光学系统视场大于60×3.5度,F数F/1~F/2.5.采用了离轴三反射镜光学系统,系统结构简单,成像质量达到衍射极限.

Abstract:In order to overcome the limit of single-mode approximation(SMA),the dispersion relation was obtained by eigen-function method.The coupling impedance was subsequently derived from the relevant equations.A lot of numerical computations and analysis were done for two typical structures of rectangular waveguide grating: the shallow grating and the deep grating.And the effects of the geometrical dimensions of the grating on high frequency characteristics of system were analyzed.Rectangular gratings models at 3cm band and 8mm band were designed and measured,The experimental values match theoretical values very well.According to linear theory,the "hot" dispersion equations were deduced,and the small-signal gain was achieved.The influences of the radius and current of the electron beam,the acceleration voltage and the geometrical dimensions of the slow-wave structure on the small signal gain were discussed.The results presented in this study provide theoretical basis on designing the rectangular grating traveling wave tube.

Abstract:分析了四方晶格光子晶体波导的高通滤波特性及其与波导宽度的关系，数值计算结果与微波段的实验结果相吻合．当光子晶体波导宽度在大约1．5a-2a（a为品格常数）的范围时，透过率频谱呈现高通滤波的特性．下限截止频率随波导宽度的增加而减小．分析了光子晶体晶胞的填充率和介电常数比对高通特性的影响．利用高通特性与波导宽度的关系设计了波长．位移传感器，计算表明测量波长的相对误差达到Δλ／λ〈0．0061。

Abstract:Two-dimensional thermal simulations of the microbolometer with a micro-bridge structure by finite element method were done. The effects of pixel size, suspended film thickness, length and width of suspended leg, down-lead, vacuum package on the temperature changes and thermal time constants of pixels induced by ilffrared radiation were analyzed. To compare, the performance of microbolometer with a cavum structure was also discussed.

Abstract:The special foam screen(SFS) is a new multi-band interference technique.In order to improve its interference effect against IR and MMW guidance,the relevant theories and experiments were studied.The results indicate that the change of bubble's diameter of SFS will lead to the rapid change of the interference effect,and the smaller the bubble's diameter is,the better the interference effect will be.So to make SFS with smaller bubbles will improve the interference effect,and it can be realized by adjusting the working pressure of the equipment to discharge SFS or by changing the material formulations of SFS.

Abstract:A new nondestructive method for discriminating varieties of waxberry by visible and near infrared spectroscopy(Vis/NIRS) was developed.First,the spectral data were analyzed by principal component analysis(PCA) for varieties clustering.Then diagnostic information was obtained from original spectra,these informations were used for pattern recognition based on ANN model.The score plot provided the reasonable clustering of the varieties of waxberry.Small quantities of principal components from PCA were used as inputs of a back propagation neural network(BPNN) with one hidden layer.100 samples were selected randomly from four varieties,then they were used to build BPNN model.This model had been used to predict the varieties of 20 unknown samples.The recognition rate of 95% was achieved.This model is reliable and practicable.So this method could offer a new approach to the fast discriminating varieties of waxberry.

Abstract:用热丝化学气相（HFCVD）法在硅衬底上制备了表面光滑、晶粒致密均匀的纳米金刚石薄膜，用扫描电镜（SEM）和原子力显微镜（AFM）观测薄膜的表面形貌和粗糙度，拉曼光谱表征膜层结构，紫外-可见光分光光度计测量其光透过率，并用椭圆偏振仪测试、建模、拟合获得了表征薄膜光学性质的n，k值．结果表明薄膜的晶粒尺寸在100nm以下，表面粗糙度仅为21nm；厚度为3．26（m薄膜在632．8nm波长处的透过率为25％，1100nm波长处达到50％．采用直接光跃迁机制估算得到纳米金刚石薄膜的光学能隙（Eg）为4．3eV．

Abstract:A method to deposit a new configuration of thermochromic VO2 films material was described, By ion beam sputtering and annealing in reductive ambient, VO2 films grown onto the glass substrate show an abrupt phase transfomation. Nanometer-scale VO2 grains are found under HRTEM and XRD observation. Four-point-test shows that the films phase transition temperature has shifted towards room temperature. The transmittances measured on different temperatures also reveal that the material owns excellent switching response to infrared light at critical transition temperature. A design of SiO2 anti-refection coating is used to improve low visible transmittance of the films, which obtains a satisfying result in experiments. It is a basic study in the applications of VO2 films to smart windows.

Abstract:Subpicosecond electrical pulses were generated and characterized in slotlines fabricated on LT-GaAs substrate for the first time, in our knowledge, by using femtosecond photoconductive correlation techniques. The measured pulse width is 0. 7ps at the generation site. The velocity of the pulses propagating in the slotlines is 1/2.3 of the light velocity in vacuum and the estimated attenuation coefficient of the electrical pulses is 20dB/mm. The pulse is broadened to 2.86ps after propagating distance of 420 along the slotlines. The measured parameters are consistent with the predicted values.

Abstract:Raman spectra of diluted magnetic semiconductor GaMnAs alloy were reported.The coupled plamon-LO-phonon(CPLP) mode has LO-like polarization properties.With increasing Mn concentration,the CPLP mode shifts to low frequency.The hole density in the alloy was determined from the ratio of the intensity of the CPLP mode to that of the unscreened LO mode in the depletion layer.The hole density increases with the increase of the Mn composition.The Raman spectra of GaMnAs alloy were measured at different temperature.It is confirmed that the hole density in the alloy increases with the increase of the temperature.

Abstract:折衍混合设计为选用廉价材料设计像质优良的红外物镜提供了新的途径．基于衍射结构的高折射率模型和传统的PWC方法。分析了折衍混合红外单透镜的光焦度分配和二级光谱；在8-12μm波段，采用GASIR2和AMTIR1红外玻璃，分别设计了可模压生产的折衍混合单片型和Petzval型红外物镜．结果表明：采用新型红外玻璃的折衍混合设计可以代替锗材料设计出具有大相对孔径，且像质优良而廉价的红外物镜．

Abstract:A transmitted scanning terahertz imaging system,which has the <100>-InAs emitter of high power,wide frequency spectrum and the detector of high sensitivity and low noise,is presented.It owns the capacity of detecting something that has been shielded by some opaque dielectric materials.Moreover,spectroscopy data at each point of the sample can be acquired by using this system.Using these data the spectroscopy images can be rebuilt.Lots of THz images of sunflower seed sample by using various data processing methods based on the Fourier transform spectroscopy are given and compared.In addition,the several important factors of the sustem,including setup,measure to the beam,data processing described in detail,which are very essential to further research and application.

Abstract:Aiming at the nonlinearity of photoresponse characteristic in infrared focal plane arrays,a approach of nonuniformity correction for IRFPA,named "curve-beeline" correction,was proposed,and the correction formula was given.The simulation results show that it has perfect performance of high precision,and less calculation.Only a few parameters are needed to storage and it is easy to implement by hardware circuit.

Abstract:One novel multi-band image fusion algorithm based on neighborhood limited empirical mode decomposition(NLEMD)was proposed.Firstly the images were decomposed by NLEMD,the parts of intrinsic mode functions(IMF's) and remnant correspondingly to each image were obtained.Then in these IMF's and remnant images,the pixel which has the maximal energy was selected for the result IMF images and remnant image.At last,the final result image was reconstructed.With the help of NLEMD,the image's detail can be extracted and the final fusion image is clearer than the source images.Experiments show that the new algorithm has more advantages in achieving high frequency details of source images than the fusion algorithm based on wavelet analysis.

Abstract:In order to solve the problem the velocity oscillation of oscillating mirror,permanent magnet synchronous motor(PMSM) was used as a drive motor.System transfer function was established.Taking into account that the scan movement is periodical,a modified repetitive contorller was proposed to control the angular velocity of scan motor.This controller used two amplifiers to adjust the system gain.As a result,the tracking accuracy was improved.Experiments show that the controll system can efficiently improve the velocity stability of oscillating mirror,and damp the osccillation of scan motor when the scan direction is changed.

Abstract:采用量子波导理论研究了Aharonov-Bohm环上臂联结stub介观结构中的电子输运性质．发现电子透射系数随stub长度和环的大小而周期振荡，能使电子输运达到100％．当系统结构确定不变时，研究了入射电子费米能量与电子透射几率的关系，结果发现当入射电子能量为某一值时，出现Fano共振效应；而且发现当入射电子能量以及环长度给定的情况下，适当调整stub长度和磁通量的大小也会导致Fano共振效应的出现．

Abstract:A new texture-based anomaly detection(TBAD) approach was presented,which segmented one image into different textures and analyzes the distribution of pixel values of the textures.TBAD assumes that the background pixel values within textures can be modeled as Gaussian distributions with mean values that vary texture-to-texture.And the anomalies(man-made objects) have values that deviate significantly from the distribution of the texture.TBAD estimates background statistics over segmented textures,so it can detect objects of any size or shape.Extensive experiments applied to the real images of small target and extend target validate the good performance of the approach.