基于变形镜本征模的模型式无波前探测自适应光学系统

模型式无波前探测自适应光学系统以其收敛速度快、校正效果好在波前无法探测的环境中具有巨大的应用潜力。基函数的产生方法及阶数多少决定了模型式无波前探测自适应光学系统的校正效果和收敛速度,文中提出以变形镜本征模作为基函数。分别以32、88及127单元变形镜作为波前校正元件建立无波前探测自适应光学系统仿真模型,利用变形镜本征模作为正交基函数对波前畸变进行校正,分析其校正效果和收敛速度。结果表明,以变形镜本征模作为基函数时,由于基函数的阶数等于变形镜的单元数,无需另外确定阶数多少,且无波前探测自适应光学系统可以获得接近理想校正时的校正效果,系统收敛所需测量的光斑强度的次数仅取决于变形镜的单元数。     

自适应光学技术在惯性约束聚变领域应用的新进展

在惯性约束聚变(ICF)领域,采用自适应光学(AO)技术进行波前控制是解决ICF激光系统中光束质量问题的重要手段.报道了"神光Ⅲ"原型装置中8套工程化自适应光学系统、未来ICF系统发展所需的大口径可拆卸变形镜(DM)样镜研制以及ICF自适应光学波前控制技术的最新研究进展.8套工程化自适应光学系统在"神光Ⅲ"原型装置上实现了到靶点的全系统静态像差校正,改善了靶点焦斑能量分布,验证了校正对打靶时X射线分布的改善效果.所研制的17单元大口径可拆卸变形镜的口径为284 mm×284 mm,行程大于±6μm,谐振频率大于500 Hz.在ICF自适应光学波前控制技术中,采用了基于哈特曼传感器近场相位测量的控制方法和基于靶室远场的随机并行梯度下降(SPGD)控制方法均能取得良好的校正性能.     

微小型自适应光学系统及其在星载光学遥感器上的应用

主要阐述了自适应光学系统的微小型化和集成化趋势,介绍了国内外微小型自适应光学系统的研究概况、水平和发展趋势,探讨了微小型自适应光学系统在空间光学遥感器上应用的系统构思及可行性,进行了空间光学遥感器主镜温度场变形的自适应光学闭环校正模拟实验,闭环后波前的Ｐ－Ｖ值小于λ／４,ＲＭＳ值小于λ／３０,改善了波前质量,为自适应光学技术在星载相机上的应用提供了有力的实验基础。     

云南天文台1.2m望远镜61单元自适应光学系统

云南天文台1.2 m望远镜61单元自适应光学系统已经完成升级改造并投入使用.该自适应光学系统主要由倾斜跟踪控制回路、高阶校正回路以及高分辨力成像系统组成.为了提高系统的跟踪精度,倾斜跟踪控制回路由两级倾斜校正回路串联而成,用于校正望远镜的跟踪误差和大气湍流引起的倾斜跟踪误差.高阶校正回路主要由一套哈特曼波前传感器、一块61单元变形反射镜以及一套高速数字波前处理机组成.系统中哈特曼波前传感器的工作波段为400～700 nm,系统成像波段为700～900 nm.在介绍61单元自适应光学系统各组成部分的基础上,对该系统的性能进行了分析,并给出了实际天文恒星目标的高分辨力自适应光学成像观测结果.     

自适应增益的SPGD算法

SPGD算法是一种应用广泛的无波前探测自适应光学控制算法。传统SPGD算法中增益系数保持某一固定值不变,随着变形镜单元数的增加,这将导致算法收敛速度变慢及陷入局部极值的概率增大。Adam优化器是深度学习常用的一种优化随机梯度下降算法,它具有增益系数自适应性调整的特点。将Adam优化器自适应调整增益系数的优势与SPGD算法结合起来用于自适应光学系统控制。分别以32、61、97、127单元变形镜作为波前校正器件,不同湍流强度的波前像差作为校正对象,建立了无波前探测自适应光学系统模型。结果表明,优化后的算法收敛速度更快,而且陷入局部极值的概率降低,并且随着变形镜单元数的增加与湍流强度的增大,算法的优势更加明显。以上研究结果为基于Adam优化的SPGD算法的实际应用提供了理论基础。     

自适应光学中变形镜的研究

大气对激光束的湍流效应是制约激光通信技术发展的一个主要因素,研究发现自适应光学技术可以有效的缓解激光束在大气中传输受到的影响。自适应光学系统由探测器、控制器和校正器3部分组成。首先由探测单元和控制单元确定控制信号,然后通过控制器改变变形镜的镜面,以达到校正波前的目的。变形镜是自适应光学系统中实现波前校正的关键器件．其特性将直接影响系统对波前光束的改善结果。通过对变形镜的工作原理、分类、技术要求和性能指标的研究．该系统补偿效果达到90％。     

61单元分立式压电变形反射镜的研制

用于校正波前误差的61单元分立式压电变形反射镜是61单元自适应光学系统（AO）的关键器件之一。由于系统对单元数（61单元）和变形量（±3μm）的要求超过以往曾研制的变形镜，对研制工作带来许多困难。我们从理论分析到工艺研究采取措施，使研制的变形镜成功用于AO系统实验。     

变形镜及其驱动器的动态响应测试研究

变形镜是自适应光学系统中的关键部件之一,它的动态响应性能直接决定了其对大气扰动的校正能力.提出了一种基于光电倍增管的测试方法,用于对变形镜及其高压驱动器进行动态响应测试.测试表明,变形镜的谐振频率优于12 kHz,促动器及其驱动器可以不失增益的工作到2kHz.     

自适应光学中变形镜的研究

大气对激光束的湍流效应是制约激光通信技术发展的一个主要因素,研究发现自适应光学技术可以有效的缓解激光束在大气中传输受到的影响.自适应光学系统由探测器、控制器和校正器3部分组成.首先由探测单元和控制单元确定控制信号,然后通过控制器改变变形镜的镜面,以达到校正波前的目的.变形镜是自适应光学系统中实现波前校正的关键器件,其特性将直接影响系统对波前光束的改善结果.通过对变形镜的工作原理、分类、技术要求和性能指标的研究,该系统补偿效果达到90%.     

双变形镜对Yb:YAG板条激光器光束质量校正技术

分析了Yb:YAG板条激光器波前畸变的基本特征,结合光斑形态和功率密度,提出了采用水冷式13单元一维变形镜和95单元二维变形镜相结合的双变形镜组合模式对Yb:YAG板条激光器的波前畸变进行闭环校正。针对输出激光的特征进行了校正需求分析和校正能力分析,以此为基础开展了一维变形镜和二维变形镜的仿真及优化设计,同步开展了哈特曼和高压驱动系统等硬件的研制。研制出的变形镜经受了满功率出光考核,验证了内循环冷却装置对水冷式变形镜的冷却效果,随后在闭环校正实验中,将激光器的开环光束质量β=9.03提升至闭环的1.98,验证了双变形镜组合模式的自适应光学系统对Yb:YAG板条激光器光束质量校正的能力。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.