优质KTP晶体腔内有效倍频效率及损耗的研究

本文报道一种高效内倍频Ｎｄ：ＹＶＯ４／ＫＴＰ激光器的输出特性以及优质ＫＴＰ晶体腔内有效倍频效率和损耗的研究结果。在泵浦功率为１９Ｗ时获得了５．８５Ｗ的连续绿光输出,相应的光－光转换效率为３０．８％。研究表明,优质ＫＴＰ晶体腔内有效倍频效率超过７０％,最高达到７４．１％;而其损耗仅为０．００７ｃｍ＾－１。     

一种快速测量非线性光学晶体损耗系数的方法

采用激光腔内倍频方法实现快速非线性光学晶体损耗测量,与常规方法不同的是用于测量晶体吸收和散射共同作用带来的损耗,而且响应时间很短,约１００ｎｓ,并具有很高的灵敏度（１０＾－４￣１０＾－５）,可望用于晶体快速损伤研究,我们对ＫＴＰ、ＬＢＯ,ＢＢＯ等块状晶体的损耗进行测试,测量精度高于５％,测量结果与文献资料比较相符合。     

KTP（KTiPO4）晶体电光开关研究

介绍了ＫＴＰ晶体电光开关的设计;利用体式ＬｉＮｂＯ３晶体、ＫＤ＾＊Ｐ晶体和ＫＴＰ晶体做了光开关（斩波）实验。在开关脉冲宽度１２０ｎｓ￣１２００ｎｓ,升降沿５ｎｓ的情况下,实验证实ＬｉＮｂＯ３晶体开关过程伴有严重的压电耦合振铃结构,不能做为体式光开关工作;而ＫＴＰ开关的综合性能是最好。     

改性KTP晶体、三镜折叠腔内倍频研究

本文利用改性ＫＴＰ晶体,进行了纯连续激光倍频实验。根据光束传输矩阵,用计算机数值法计算了三镜折叠腔不同谐振腔参数所对应的稳定区,对Ｎｄ：ＹＡＧ／ＫＴＰ进行腔内倍频,实验获得了３－５Ｗ 纯连续绿色激光输出。其实验结果与理论计算值基本相符。     

多波长激光器的研究

以Ｎｄ：ＹＡＧ激光晶体为工作物质，用非线性晶体ＫＴＰ进行腔内倍频，倍频光泵浦染料激光器。从而在一台机器上实现了１０６４ｎｍ、５３２ｎｍ和６３０±５ｎｍ三种波长的激光输出。     

晶体温度对L泵浦Nd：YVO_4／KTP腔内倍频激光器输出的影响

研究了ＬＤ泵浦Ｎｄ：ＹＶＯ４／ＫＴＰ腔内倍频激光器中激光晶体与倍频晶体的温度对器件基频与倍频输出的影响。用国产１Ｗ激光二极管作泵浦源,通过选择合适的Ｗｄ：ＹＶＯ４和ＫＴＰ的工作温度,在泵浦功率为６０４．２ｍＷ时获Ｔ得１３３．６ｍＷ的绿光输出,光－光转换效率为２２．１％。     

高转换效率连续内腔倍频绿光激光器

高转换效率连续内腔倍频绿光激光器我们采用国产输出功率１Ｗ的半导体激光器泵浦的Ｎｄ：ＹＶＯ４内腔倍频激光器，获得能量转换效率为１２％。Ｎｄ：ＹＶＯ４晶体尺寸为３ｍｍ×３ｍｍ×１ｍｍ，Ｎｄ掺杂浓度２％，倍频晶体ＫＴＰ置入腔内。激光二极管输出经准直－聚光光...     

大功率全固化绿光激光器

大功率全固化绿光激光器最近，我们利用中国科学院物理所生长的Ｎｄ：ＹＶＯ４，ＫＴＰ晶体和福建物构所生长的ＣｈＯ晶体，采用角度相位匹配的ＫＴＰ腔内倍频和温度相位匹配的ＬＢＯ腔内倍频，成功地研制了一台ＬＤ泵浦的全团化大功率绿光激光器。对ＫＴＰ，ＬＢＯ这两种...     

铁电晶体铌酸钾锂的倍频性能研究

用cw-Ti:sapphire激光对不同组成的熔体中生长得到的铌酸钾锂晶体进行了倍频性能研究。实验结果表明,只有当晶体中Li离子含量达到一定值时,铌酸钾锂晶体才具有非线性光学效应;晶体中Li离子含量越高,倍频性能越好,Li2O浓度为26mol％的熔体中生长得到的铌酸钾锂晶体的倍频实验的结果表明,该晶体能对820－960nm的近红外cw-Ti:sapphire激光倍频实现蓝绿光输出,具有较好的倍频性能。     

不同掺杂浓度Tm^3＋在YVO4晶体中光吸收各向异性的研究

在室温下测量了５种没的掺杂浓度（６．０ａｔ％,４．０ａｔ％,３．２ａｔ％）ＹＶＯ４;Ｔｍ＾３＋在２００－９００ｎｍ波段的吸收光谱。结果指出,Ｔｍ＾３＋掺杂的ＹＶＯ４晶体光 Ｔｍ＾３＋浓度而变化,每一谱带形状和结构是相似的;而高掺杂浓度Ｔｍ＾３＋的光吸收相对强度比低掺杂浓度的ＹＶＯ４吸收强;不同晶轴ＹＶＯ４晶体吸收质显示出各向异性。观察到在ａ晶轴含π和σ偏振的吸收谱。简要地讨论了Ｔｍ＾３＋,ＹＶＯ４     

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.