10.6μm激光器一级输出高衍射效率闪耀光栅的研制

建立了实际刻划光栅的物理模型,给出了相应的衍射效率表达式,并研制出了在Littrow安装下一级衍射效率达到97．2％的大功率10．6μm红外激光器用反射式闪耀光栅。实际刻划光栅通常都存在零级面,采用傅里叶分析方法可以推导出计算带有零级面的闪耀光栅衍射效率的一般表达式,由理论分析可知,零级面是造成闪耀光栅衍射效率下降的原因之一。在工艺过程中．通过加大刻划负载使零级面减小,加大侧向压力强化对闪耀面的抛光等,是提高光栅刻槽质量和衍射效率的有效途径。     

9.77 μm激光器零级耦合输出选频振荡光栅的设计和研制

建立了实际刻划光栅的物理模型，给出了相应的衍射效率表达式，进而阐述了红外激光器零级耦合输出选频振荡闪耀光栅的设计原理。根据理论分析结果，采用调整刻划负载控制三角槽形闪耀光栅零级面。双向逐步逼近1级和零级衍射效率设计值的方法和工艺，研制了在利特罗(Littrow)安装下1级衍射效率为86．5％，零级衍射效率为10．3％的9．77μm红外激光器零级耦合输出选频振荡镀金闪耀光栅。检验结果表明，由加工误差引入的1级和零级衍射效率与设计中心值的偏离量分别仅为0．6％和3％。     

低密度台阶形闪耀光栅的制作

介绍了制作低密度闪耀光栅的过程,在制作时,对传统的制作过程进行了改进,有效提高了制作质量。以40μm闪耀光栅为例介绍了制作的过程,得到了良好的光栅表面形貌,并且闪耀级次的衍射效率达到了70%以上。相比传统的制作方法,效率提高了5%～10%。对比了理论上的衍射效率,分析了实验误差,发现把存在对准误差的光栅进行处理将会有效地提高其衍射效率,为进一步提高闪耀光栅的衍射效率提供了依据。     

宽波段凸面闪耀光栅优化设计

凸面闪耀光栅是研制高光谱分辨率成像光谱仪的关键元件之一,一般凸面闪耀光栅的有效波段范围较窄,较难满足宽波段成像光谱仪对光栅衍射效率的需求。为拓宽仪器观测波段,对其中凸面闪耀光栅进行了优化设计。以0.4~2.5 m波段Offner型成像光谱仪为例,研究了凸面光栅单衍射级和双衍射级共路两种色散结构,采用分区闪耀光栅和双角闪耀光栅来提高宽波段范围内的衍射效率。优化设计了两种双闪耀光栅在不同色散结构下的槽形,用标量理论和有限元分析等方法对光栅衍射效率进行了计算。结合仪器信噪比,给出了满足成像光谱仪不同需求时所适用的光栅。     

基于二维激光告警的闪耀光栅设计

现有光栅衍射型激光告警中,正弦光栅存在1级衍射效率较低,闪耀光栅在闪耀波长附近0级和-1级衍射效率很低,这两种光栅的缺点都降低了激光告警的可靠性。为此文中提出了一种改进型闪耀光栅。将两闪耀光栅反相对接,并且中间留一定无光栅空间,此改进可提高波长在闪耀波长附近0级和-1级的衍射效率,将有效克服传统闪耀光栅的漏报警现象。设计加工了闪耀波长为800 nm的改进型闪耀光栅,理论分析了0级和1级衍射效率;采用波长为808 nm和850 nm的光,对改进型闪耀光栅进行二维激光告警实验测试,实验结果表明,在波长为闪耀波长附近光入射时,改进型较普通闪耀光栅的0级和-1级衍射强度有很大提高,能够被CCD有效探测。该改进型闪耀光栅可有效提高二维激光告警系统的可靠性。     

高衍射效率凸面闪耀光栅的研制

基于严格耦合波分析,研究凸面闪耀光栅的衍射特性;采用全息光刻-离子束刻蚀法制作中心周期为2.45μm、曲率半径为51.64 mm、口径为17 mm的凸面闪耀光栅,闪耀角为6.4°,顶角为141°。结果表明,在整个可见-近红外波段,所制作光栅的1级衍射效率大于40%,在闪耀波长处1级衍射效率大于75%。     

CO激光器光栅二级衍射调谐实验研究

在理论分析基础上,利用闪耀光栅二级衍射为正反馈和采用反射率为80%的平行平面锗镜作为输出镜,进行混合型轴流CO激光器光栅选支,波长分辨率提高了一倍,在激光分离铀所需的5.33μm附近三条谱线获得了输出.分析表明,还可以进一步增大输出功率.     

消偏振二维二元闪耀光栅设计

为减小成像光谱仪的偏振敏感度并提高其定量化探测精度,提出一种透射式消偏振二维二元闪耀光栅。它在两个正交方向上都具有周期性槽形单元,每个槽形单元包含7个子周期。每个子周期的介质占空比在两个方向上是独立的,可同时调制TE和TM偏振态的等效折射率,以此优化光栅偏振特性。本文将等效介质理论拓展到二维情况,设计了以熔石英为基底,工作波段为0.6~0.8μm的高衍射效率消偏振二维二元闪耀光栅。光栅两正交方向周期分别为3.31μm和0.473μm。仿真结果表明,在参考波长0.7μm处TE和TM偏振态衍射效率分别为79.5%和79.6%,0.6~0.8μm波段范围内TE和TM偏振态衍射效率均高于70%,偏振敏感度低于2.6%。与一维二元闪耀光栅相比,二维二元闪耀光栅具有高衍射效率、低偏振敏感度和易制作的优势。所得结论可用于指导实际应用中透射式二元闪耀光栅的设计,可望在光栅型高光谱成像仪中得到应用。     

变栅距闪耀光栅相对衍射效率的计算方法

提出了一种变栅距闪耀光栅相对衍射效率计算方法,它是基于变栅距闪耀光栅衍射强度分布公式得出的。该方法简洁、有效,虽然有一定的近似性,但在工程设计上仍有较强的指导性。此外,还得出变栅距闪耀光栅参数对其衍射效率的影响规律,对优化制作工艺提供了理论依据。     

非对称全息方法制作闪耀光栅的模拟与分析

为了实现全息方法制作闪耀光栅,在对称全息光栅制作方法的墓础上,设计了一种非对称光路进行曝光。模拟了特定显影条件下光栅槽形及其衍射效率光谱。并与理想三角形闪耀光栅比较。结果表明：模拟槽形具备闪耀光栅槽形特征,其正一级衍射效率谱线与相应闪耀光栅非常接近。     

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.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.