2kWCO2激光器孔栏限模腔的研究

本文实验研究了几种不同菲涅耳数的孔栏限模平凹腔的输出特性,讨论了光栏孔径、腔结构参数、输出镜透过率和光轴失调等对激光功率和光束模式的影响。     

正支共焦非稳腔的失调特性实验分析

在理论分析基础上,采用Hartmann-Shack（H-S）波前传感器方法实验分析了无源正支共焦非稳腔失调后输出光束像差特性。结果表明,腔内倾斜像差对光束强度分布有显著的影响,约1′的腔内倾斜即可使强度分布呈现明显不均匀,并使相位中的倾斜像差Zernike系数增大。但小的腔内倾斜像差不会使波面中的高阶像差发生明显变化,当引入较大的腔内倾斜时相位中的离焦、像散等高阶像差则有所增大。大菲涅耳数,且腔长较长的非稳腔对于离焦像差有一定的容限度。因此,在进行腔内像差自适应校正时,应首先考虑腔内倾斜像差的校正。     

射频激励CO2波导激光器的放电技术

本在理论上详细论述了如何在激光头的射频电极上并联上一些电感，并在激光头和电源之间加一可调匹配网络以达到这一目的，并在实验上实现了矩形波导以及１＊３波导列阵大面积的均匀放电，得到了激光输出。     

外腔半导体激光器阵列波长稳定的实验研究

自由运行的半导体激光器列阵输出激光谱线较宽、中心波长易漂移.为此,本文采用体全息光栅(VBG)构成外腔半导体激光器阵列(EcLD)系统,利用体光栅能够稳定波长、压窄线宽的特点,从而克服上述缺点.实验表明:采用了VBG外腔反馈后,在最好的情况下,LDA的输出光谱宽度从自由运行时的2.3 nm压窄到了O.96 nm;在测试的环境温度变化范围内(14～3l℃),LDA的峰值波长稳定在体光栅布拉格波长808 nm处,输出光的线宽维持在1.14 nm之下;并且,在测试的偏置电流变化范围内(7-13A)峰值波长和谱宽无明显变化.     

半导体微腔激光器瞬态特性的分析

建立了反映半导体微腔激光器特性的模型,借助计算机手段,运用Matlab软件直接给出了半导体微腔激光器瞬态响应的仿真结果及载流子密度和光子密度的相图,分析了自发辐射因子、注入电流和腔长对微腔器的激射阈值、延迟时间、驰豫振荡频率和光输出等参量的影响。该模型及有关结合为半导体微胶激光器的工艺制作,改善的高频调制特性和优化器件提供了理论依据。     

垂直腔面发射激光器的研究开发现状及其应用

由于人们对超长距离、超高速光纤网络和高性能、低成本光互连网以及光学存储密度不断提出更高的要求，从而诞生了垂直腔面发射激光器（VCSEL）。它具有常规半导体器不可替代的极其优良的性能，因此受到国内外科技界和企业 高度关注，一直蓬勃发展，在短短的12年间，其在结构、材料、波长和应用领域都到迅速发展，部分产品已进入市场，本文尝试对VCSEL的器件性能，开发现状及应用作一简要概述。     

微片激光器谐振腔表面反射膜研究与展望

主要对微片激光器谐振腔的工作介质和腔端面反射膜进行讨论,其中谐振腔的工作介质主要包括晶体、陶瓷和玻璃3种,针对不同的光学器件应选用合适的工作介质。分析研究了谐振腔端面反射膜的膜材料的选择以及反射膜的结构设计,其中膜系结构设计主要包括膜层排列、膜层数和膜厚3个方面,还简要介绍了常用的反射膜制备工艺。最后,展望了微片激光器的技术和应用发展趋势。     

基于视觉的环形激光陀螺自动调腔系统

针对激光陀螺调腔,设计了一种基于视觉的自动调腔系统.采用基于统计的图像分析方法,对激光陀螺光学谐振腔中的光阑和光束进行定位.根据几何光学,分析了谐振腔中反射镜位置失调与光束偏移之间的关系,并设计了基于图像的闭环位置控制律,对反射镜的位置进行调整.实验表明,该系统能够完成对光阑和光束的自动识别,能够较好地实现激光陀螺的调腔.     

Theoretical investigation of phase-based all-optical logic gates based on AlGaAs microring resonators

We propose and numerically verify a phase-based all-optical logic gates (AND, OR, XOR, NOT, NAND, NOR and XNOR, i.e. all seven basic logic gates) operation scheme based on cascaded AlGaAs microring resonators. The logic function realization is supported by the signal light phase change and extraction, the phase control in this scheme depending on cross phase modulation (XPM) in the AlGaAs microring. By inputting a non-return zero (NRZ) intensity signal as pump light, the probe light (continuous-wave, CW) will experience different phase shift and then a phase-based logical function can be obtained in this process. By choosing different pump power level, reference phase and the output port of a Mach–Zehnder interferometer (MZI), all seven basic logic operations can be realized by using the same device. The modulation depth, bandwidth and minimum power requirement of this scheme have also been discussed in detail.     

基于转镜的激光照明系统设计及实验研究

为了实现区域内快速运动微小目标的激光辅助照明,提出了利用转镜与点激光器组成扇形激光辅助照明系统的设计方案.详细论述了转镜面数、外接圆直径及转速与激光照明光幕的关系.给出了该激光照明系统下目标被照亮部分的平均激光功率密度与点激光光源功率、激光扫描速度、点激光发散角、相机曝光时间和目标与激光光源距离之间关系的计算公式.仿真...     

Theoretical investigation of phase-based all-optical NOT,XOR and XNOR logic gates based on AlGaAs microring resonators

We propose and numerically verify a phase-based all-optical logic gate (NOT, XOR and XNOR) operation scheme based on cascaded AlGaAs microring resonators. Phase control in this scheme depends on cross-phase modulation in the AlGaAs microring. The realization of NOT logic depends on the π phase shift of light transmission, and this π phase shift can be naturally obtained in microring resonators in the under-coupled state. Inputting a non-return zero intensity signal as pump light, the probe light (continuous wave) will experience a different phase shift and a phase-based logical function can be realized in this process. The bandwidth and the minimum power requirement of this scheme are also discussed in detail.     

A study of uv preionization pulsed tea CO2 laser

Abstract

A uniform volumetric discharge was obtained by means of an auxiliary UV preionization in a home‐made TEA CO₂ laser. The maximum output pulse energy of this laser system was about 12J per pulse with a pulse duration of 80 ns. The ratio of electric field to neutral particle density (E/N) in this laser was 7.6×10^‐16 V cm². The peak power and pulse shape of the laser were studied. The time delay between the predischarge and the maindischarge during the stable operation of this laser system has also been studied. It was observed that the laser was operating with uniform glow discharges when the time delayed between the predischarge and the maindischarge was in the range of 1.0 μs to 6.0 μs. The spark array used as a preionizer for producing the UV radiation in this system is new, simple, durable, and can be easily fabricated.     

金属材料水导激光加工实验研究

金属材料的激光加工目前正向着低表面粗糙度、小热影响区及大深径比结构的趋势发展。新近发展了一种基于激光-水射流耦合原理的水导激光加工技术,本文阐述了水导激光加工技术的基本原理及其相对于传统激光加工方法的优势,基于激光-水射流耦合原理构建了一套水导激光加工设备,对多种金属材料进行了水导激光加工实验。利用超景深显微镜对加工工件表面进行了观测与分析,发现两种金属材料加工得到的盲孔边缘规则圆滑,切槽的边缘平直无毛刺,没有热影响区。实验结果说明对金属材料的水导激光精密加工具有可行性且有重要的应用价值。     

A study of parameters affecting the continuous CO2 laser cuts

Abstract

This work attempts to discover, by experimentation, some of the parameters governing cutting efficiency in perspex of a continuous CO₂ laser. The experimentation took the form of taking cuts in specimen pieces with the laser. While varying the parameters of speed of cut and position of the focal plane of the laser beam relative to the surface of the perspex, all other parameters were kept constant. These experiments produced conclusive ideas of the optimum position of the focal plane and the best speeds for cutting perspex at the same time producing the best cut quality obtainable. When the theoretically predicted minimum cut width is compared with the experimentally obtained results, the agreement is found to be almost exact.     

弱磁场对SnO2薄膜性能的影响

利用等离子体增强化学气相沉积（PECVD）技术制备了SnO2薄膜。实验中通过改变磁镜场的磁镜比和磁场大小,研究了弱磁场对SnO2薄膜方块电阻及电阻分布的影响。实验结果表明,随着磁比和磁场强度的增加,SnO2薄膜的方块电阻在降低,且电阻分布变得比较均匀;但是,当磁镜比超过5．5时,SnO2薄膜的电阻分布变得越来越不均匀。     

柱塞式校准器检定临界流喷嘴的实验研究

介绍了一种采用标准柱塞结构的临界流喷嘴校准器的原理和组成.根据临界流喷嘴的流量特性建立了检定数学模型,同时建立工作腔气体状态方程,并进行分析.对该校准器工作腔的压力和温度进行了大量实验研究,结果表明,工作腔内气体的压力和温度在检定过程中能够保持稳定,有益于提高检定的精度和效率.利用该校准器进行临界流喷嘴背压比试验,调节被测喷嘴背压比,检测其实际流量,得到与理论曲线相一致的流量特性曲线,从而为临界流喷嘴的特性研究提供了一个良好的手段.     

弱磁场对SnO2薄膜性能的影响

利用等离子体增强化学气相沉积（PECVD）技术制备了SnO2薄膜。实验中通过改变磁镜场的磁镜比和磁场大小,研究了弱磁场对SnO2薄膜方块电阻及电阻分布的影响。实验结果表明,随着磁镜比和磁场强度的增加,SnO2薄膜的方块电阻在降低,且电阻分布变得比较均匀;但是,当磁镜比超过5．5时,SnO2薄膜的电阻分布却变得越来越不均匀。