基于微透镜阵列的半导体激光器堆栈匀化系统

半导体激光器由于自身波导结构的不对称性导致光强分布不均匀而限制了其应用,为了对半导体激光光束进行整形以获得均匀光斑,设计了一种基于微透镜阵列的半导体激光器堆栈匀化系统。分析了微透镜阵列对半导体激光的匀化原理和光束匀化过程,通过分析微透镜边缘衍射对匀化光斑影响确定了微透镜孔径范围,采用近轴矩阵光学推导了目标光斑发散角。结合实例对微透镜阵列光束匀化系统进行了仿真和实验验证,实现了均匀性为91.89%的均匀光斑。     

光学胶膜液体可变焦微透镜阵列

微透镜阵列在光束匀化、波前测量、集成成像等领域有广泛应用。设计了一种基于光学胶膜(Optically Clear Adhesive, OCA)的液体可变焦微透镜阵列。采用矩形排列的硅微孔阵列控制单个透镜的孔径和排布,并以OCA光学胶膜和去离子水作为微透镜阵列的塑形材料。通过调整微流体腔内液体注入的体积实现对透镜焦距从1.46~10.44 mm的调整。依据聚焦与成像实验证实了微透镜阵列具有良好的均匀性。最后,将该微透镜阵列应用于激光光束匀化整形,通过一对微透镜阵列实现了光束匀化整形。进一步通过固定一对微透镜阵列的间距实现匀化光斑尺寸在7.2~8.4 mm内可调,为匀化光斑尺寸可调提供了新思路。     

半导体激光器光束匀化系统的光学设计

为了提高半导体激光器光束的均匀性,设计了非球面与微柱透镜阵列相结合的匀光系统。快轴方向利用光线追迹设计非球面匀化透镜;慢轴方向采用微柱透镜阵列对光束进行分割叠加。半导体激光器输出光束通过该匀光系统,在目标面上可以得到能量匀化的方形光斑。利用Zemax光学软件对半导体激光器单管和阵列进行匀化仿真,验证了该匀化系统应用于半导体激光器整形的可行性,得到了目标面动态范围变化对均匀度的影响程度,研究了微柱透镜阵列间距变化及快轴匀化透镜旋转对光斑均匀度的影响。单管和阵列在输出面上的光斑均匀度均大于90%,能量传输效率分别为95.4%和96.2%。该设计结果对半导体激光器光束匀化具有一定的参考价值。     

衍射微透镜阵列用于面阵半导体激光光束匀化

提出了一种用衍射微透镜阵列对面阵半导体激光光束进行匀化的方法,解决了折射型微透镜阵列难于实现高填充因子、高精度面型的难题。基于标量衍射理论,设计了具有多阶相位结构的衍射微透镜阵列,推导了半导体激光从输入面到输出面的光场计算公式。数值模拟了非成像型微透镜阵列光束匀化系统,并对其进行了实验验证。当衍射微透镜的口径为0.125mm,相对孔径为0.1,相位台阶数为8时,测得焦斑在快轴方向的不均匀性为12.34%,能量利用率为96.6%;慢轴方向的不均匀性为5.42%,能量利用率为95.74%。实验结果与理论模拟的结果吻合,验证了衍射微透镜阵列光束匀化系统模型的可行性。     

多孔径光束积分激光匀束器理论与设计

分析了多孔径光束积分匀束器的基本原理和设计理论,分别设计了衍射型和成像型微透镜阵列激光匀束器,将高斯光束整形为平顶光束。光线追迹的结果表明,当微透镜阵列的菲涅尔数较大时,两种匀束器都能获得良好的匀束效果,而成像型能比前者提供更好的光束均匀性和边缘坡度。此外,入射光的准直性能会影响匀束效果,当入射光发散角较大,超过微透镜数值孔径时会导致像面光斑出现明显旁瓣,无法实现正常的匀化。     

基于微透镜阵列光束均匀化的傅里叶分析

为了提高高功率固体激光器泵浦光束的均匀性,分析了成像型和衍射型微透镜阵列匀化光束的基本原理,基于菲涅尔衍射和傅里叶变换公式,推导出了微透镜阵列焦平面上光强分布的解析表达式,比较了两种光束微透镜阵列对光束匀化的效果。同时,研究了成像型微透镜阵列子透镜的相对孔径及微透镜阵列间距对光强分布的影响。结果表明,成像型微透镜阵列具有更好地匀化效果,且子透镜孔径是影响光束均匀性最主要的因素。     

"神光-Ⅱ"装置靶面均匀辐照系统的优化设计

利用小透镜列阵均匀化技术 ,针对“神光 Ⅱ”出射光束近场光强特殊分布 (有大面积光强为零的区域 )的情况 ,通过对主聚焦透镜及小透镜列阵组合系统的优化设计 ,实现了靶面光强的大光斑均匀辐照 ,并利用其驱动平面铝靶 ,获得了具有大范围良好平面性的冲击波发光信号。     

基于微透镜阵列的光束积分系统的性能分析

为了提升高功率固体激光器抽运光束的均匀性,研究了成像型和非成像型光束积分系统光束匀化机理。从光斑尺寸、最大入射角及光斑均匀性三个方面,详细对比了两种积分系统的性能特点。分析表明,成像型光束积分系统不但具有更好的匀化效果,相比非成像型还降低了对半导体激光器(LD)光束准直的要求,并且可调整微透镜阵列间距实现光斑尺寸的改变,拓展了系统应用范围。经实验测试,在照明范围内LD阵列光束经成像型积分系统后光斑不均匀性小于10%。     

基于透镜阵列的眼科准分子激光光束整形与匀光系统

为提高屈光手术中准分子激光的能量利用率和光斑均匀性,设计了一套由双排透镜阵列和会聚透镜组成的准分子激光光束整形与匀光系统。借助近轴光学计算发现,通过调节双排透镜阵列的间距可以改变聚焦光斑的尺寸,通过调节透镜阵列与会聚透镜之间的距离可以改变光学系统的整体长度而不影响聚焦光斑的形态。利用光线追迹方法对该系统进行了模拟分析,在会聚透镜像方焦平面上获得了呈均匀分布的方形聚焦光斑,并给出了聚焦光斑尺寸随双排阵列透镜间距的变化过程。分析了接收面离焦对光斑尺寸和能量分布产生的影响,指出所设计的光束整形与匀光系统可以满足准分子激光屈光手术对激光光斑质量的要求。     

用于低温多晶硅制备的线光束整形系统

设计了一套用于准分子激光低温多晶硅制备的线光束整形系统。系统中设置的光斑转换模块可使原始光束截面横纵倒置;利用扩束模块对原始光束的短轴进行准直,其扩束倍率可限定短轴光束尺寸,以配合短轴光束均匀模块的孔径;采用基于透镜阵列的长轴、短轴光束均匀模块可在提高光斑能量分布均匀性的同时,约束光斑尺寸;系统中设置了投影模块,可将光束投影于工件表面。为了实现系统中光学原件的精密定位,设计并加工了配套的机械调节结构;结合仿真实验,讨论了阵列单元的中心偏差及工作面的偏离对线光斑质量的影响。利用该线光束整形系统对自行研制的大能量准分子激光光源进行整形,实测的系统能量传递效率为33%,工件表面的光斑尺寸约为100mm×0.3mm,平均能量密度为470mJ·cm~(-2),长轴能量分布均匀度为93.95%,满足退火技术的要求。     

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.     

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.     

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.     

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.     

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.     

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.