高斯激光辐照焦平面探测器温度场分析与仿真

为了研究激光辐照焦平面探测器的温度效应,采用ANSYS有限元软件建立高斯脉冲激光辐照锑化铟红外焦平面探测器的3维结构分析模型,并对该探测器3维温度场效应进行了研究。结果表明,激光辐照下,探测器最大温度出现在最上层的锑化铟芯片上,探测器最大温度达到锑化铟芯片熔点温度798K时,将会引起探测器的热熔融损伤,且熔融损伤阈值受到脉宽、光斑半径等激光参量的影响;高斯脉冲激光辐照下,探测器中各层材料的温度场分布呈现出非连续的高温极值区域,其主要原因是位于锑化铟红外焦平面探测器中间层相间分布的铟柱和底充胶具有迥异的热学性质,并且造成探测器温度场云图中锑化铟芯片、底充胶与硅读出电路高温极值区域形成类似于互补的高温分布。这为进一步研究温升效应引起的应力场分布、提高探测器激光防护性能提供了重要的理论分析依据。     

CO_2激光辐照对熔石英表面形貌与应力分布的影响

采用不同光斑直径的10.6μm CO2激光束对熔石英表面损伤进行辐照处理。实验发现,对于50μm以下的损伤点,单发激光脉冲辐照即可使得激光损伤阈值恢复到基底完好区域的水平,对于在50~300μm之间的损伤点,采用低功率较长时间辐照后逐渐增加功率修复的方式可以彻底消除材料内部更深的裂痕。对不同尺寸光斑辐照后的应力分布研究表明,激光束尺寸、激光功率和激光作用时间是影响材料体内应力分布的主要因素,相比较而言,激光尺寸对应力分布的影响更为明显。对前后表面损伤分析表明,当辐照区域置于入射面时,辐照带来的微小环状凸起会造成后表面环形调制损伤,是损伤的最薄弱环节,当辐照区域置于后表面时,烧蚀主要影响阈值的整体提升。     

CW CO2激光对PV型InSb探测器的破坏效应

通过测量光伏型锑化铟探测器在不同功率密度、不同辐照时间的CW CO2激光辐照时性能的变化,得到其破坏阈值区间.理论上用一维热模型计算了探测器在激光辐照过程中的温升,结果表明,PV型InSb探测器的破坏效应源于连续波激光辐照过程中温升达到InSb材料熔点时其pn结退化为电阻.     

红外成像系统激光干扰饱和串音效应的仿真

分析了激光辐照下,红外成像系统饱和串音效应的机理,计算了投射到探测器表面的激光光斑半径及能量分布,建立了红外成像系统激光干扰的饱和串音模型,并利用系统仿真软件,模拟了激光辐照前后的系统成像效果,证明了激光干扰对红外成像系统成像质量的影响。     

扫描型星载光电探测器激光干扰建模与仿真

激光干扰是目前对抗光电探测器的重要手段之一。从激光对光电探测器的干扰机理出发,研究了激光远场光斑大小,探测器表面激光覆盖面积,改进了扫描型星载光电探测器激光入瞳模型。为辐照到探测器光敏面的激光功率密度建立了模型,并以1.06μm激光辐照HgCdTe红外探测器为例,通过仿真计算,证明了星载低功率激光器对星载光电探测器干扰的可行性。     

CO2激光对氧化钒成像设备干扰实验研究

随着红外成像技术发展,非制冷氧化钒探测器在多个领域得到了应用,其在激光辐照下的热效应如何,也成为了当前研究方向之一。本文首先分析了氧化钒成像探测器结构和工作原理。其次开展了激光辐照饱和及点损伤条件下,106μm脉冲激光辐照氧化钒成像设备实验。在激光辐照饱和条件下,光斑中心像元出现饱和现象,激光辐照结束后,该像元响应较辐照前增加了约20个灰度;该像元周围像素出现了环状异常,非均匀性校正后探测器恢复正常;在激光辐照点损伤条件下,出现了圆环干扰效应,光斑中心像元出现了损伤,即使非均匀性校正也无法恢复;给出了相应激光功率密度。根据实验结果,对衍射效应进行了仿真,指出衍射、探测器热效应及热量“溢出”是导致探测器像元异常像素数大于辐照光斑的原因。本文对非制冷氧化钒探测器研制及干扰效应研究具有重要参考意义。     

10.6μm激光辐照碲镉汞红外探测器热损伤研究

研究了Hg Cd Te红外探测器的结构以及材料特性,阐述了激光损伤Hg Cd Te红外探测器的机理,建立了Hg Cd Te红外探测器三维仿真模型,利用有限元分析法,对10.6μm CO2激光辐照Hg Cd Te探测器的温度变化情况进行了仿真,并通过参考已有文献的实验数据,验证了模型的准确性。当Hg Cd Te探测器受到峰值功率密度为5×107 W/cm2的单脉冲激光辐照时,Hg Cd Te晶体的Hg离子开始析出,探测器性能降低,并不可恢复;当激光峰值功率为108 W/cm2,探测器Hg Cd Te晶体开始出现熔融现象,此时激光能量密度为1 J/cm2;当激光峰值功率为2×108 W/cm2时,铟柱达到熔融温度,探测器会出现铟柱脱落现象,被彻底损坏。     

激光对天基红外系统预警卫星光电探测器的干扰效能研究

从分析预警卫星光电探测系统入手,在介绍了激光干扰光电探测器机理的基础上,研究了激光在大气传输中的衰减效应及远场激光光斑尺寸估算,建立了激光辐照星载光电探测器的远场能量密度模型,并以1.06μm激光辐照星载HgCdTe探测器为例,通过仿真计算,定量地评估了激光武器对天基红外系统预警卫星光电探测器的干扰效能。     

室温锑化铟在探测器阵列靶中应用问题研究

锑化铟探测器阵列靶是红外激光光斑测量的重要仪器。仪器中的光导型锑化铟探测器对温度比较敏感,这容易使后级信号处理电路的静态工作点出现温度漂移现象,影响阵列靶探测精度。针对这一情况,设计了一个可以根据环境温度实时调整静态工作点的系统,有效地解决由于探测器静态阻值随温度变化而引起的静态工作点的漂移问题,为室温锑化铟红外探测器在各种环境下的应用提供了一套有效的解决方案。     

强激光辐照探测器材料力学效应的解析研究

当探测器材料受激光辐照时,由于吸收激光的能量,从而在材料体内形成一个不均匀分布的温度场,由于材料是连续分布的介质,其各部分不能自由地膨胀,相互制约,从而产生热应力。一旦靶材中产生的热应力超过靶材的破坏强度,便会使材料造成永久性的损伤破坏。当辐照激光功率密度不高时,产生的热应力对靶材的破坏是一种十分重要的破坏机制。采用解析方法,研究了连续波化学激光辐照探测器材料时产生的温升及热应力,讨论了不同激光参数（ 强度、波型、波长及脉冲持续时间） 与温度变化及热应力之间的变化关系,以及造成探测器材料热应力损伤的激光强度阈值。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.