光热偏转光谱检测水中氟离子含量

本文应用光热偏转光谱（ＰＤＳ）检测水中微量元素氟离子的含量。它克服了常规光度方法测量溶液浓度中存在的二个干扰因素的影响，提高了检测灵敏度。讨论了ＰＤＳ信号随调制频率、泵浦光功率、探测光功率的变化，优化了测量装置的参数选择。     

强激光光学元件表面功率谱密度函数估计

在扼要描述了光学件表面轮廓测量中功率谱密度（ＰＳＤ）函数的基本概念、公式和应用基础上,重点讨论了光学元件表面低频和中高频空间频率ＰＳＤ对光场分布的影响,并给出了强激光光学元件表面ＰＳＤ函数曲线的几个实测结果。     

Na（4D）＋Na（3S）=Na（4F）＋Na（3S）碰撞能量转移截面

利用双光子吸收，将Ｎａ（３Ｓ）原子激发到４Ｄ态，测量了Ｎａ（４Ｄ）＋Ｎａ（３Ｓ）＝Ｎａ（４Ｆ）＋Ｎａ（３Ｓ）碰撞能量转移截面，因为直接由４Ｆ→３Ｄ的荧光不能探测，所以检测３Ｄ→３Ｐ级联荧光讯号。结合基态钠原子密度的测量，给出了截面值σ４Ｄ→４Ｆ－１．３×１０＾－１４±２８％（ｃｍ＾２）。     

碳氢碳氟表面活性剂混合胶束的NMR和ESR研究

用ＮＭＲ，ＥＳＲ和表面张力测量研究了３－十二烷氧基－２－羟丙基磺酸钠（ＳＤＥＨＳ）与全氟辛酸钠（ＳＰＦＯ）混合溶液微环境性质，表面张力测定表明长链烷基磺酸盐中嵌入羟丙基后，其表面活性提高，而与ＳＰＦＯ混合溶液的表面活性高于单一的ＳＤＥＨＳ和ＳＰＦＯ，ＮＭＲ和ＥＳＲ研究表明，ＳＤＥＨＳ的碳氢链与ＳＰＦＯ的碳氟链之间有强烈的相互作用，ＳＤＥＨＳ与ＳＰＦＯ形成混合胶束，混合胶束“界面”的微观粘度较ＳＤＥ     

电感耦合等离子体原子发射光谱的现代谱估计

用现代谱估计方法对电感耦合等离子体原子发射光谱（ＩＣＰ－ＡＥＳ）及其信号特性作了讨论。本工作用现代谱估计技术中的自回归模型（ＡＲ）方法计算功率谱。采用Ｌｅｖｉｎｓｏｎ－Ｄｕｒｂｉｎ递归算法计算ＡＲ模型的参数,然后用这些参数计算功率谱。用实际的ＩＣＰ－ＡＥＳ光谱和测量信号所得的结果表明,采用谱估计方法可以对ＩＣＰ－ＡＥＳ光谱的频率构成和特性作进一步深入的理解。     

放射光强和背景光对二维光电位置敏感器件干扰的影响

光电位置敏感器件（ＰＳＤ）是一种可直接对其光敏面上的光斑位置进行检测的光电器件，柯构成非接触高精度动态测量系统，光电位置２器件在使用中的关键问题是如何定量确定入射光强的大小和克服各种背景光干扰，以提高检测的精度和可靠性，根据光电位置敏感器件的原理和光眯位置方程，找到有背景光作用于光电位置敏感器件上的位置输出的光关系及背影光导致的位置误差的实验数据，同时八射光强度对光电敏感器件输出误差最小的定量关系     

C60／PSt复合材料的反饱和吸收与光限幅特性

报道了Ｃ６０／ＰＳｔ（Ｐｏｌｙｓｔｒｅｎｅ）复合材料的制备，测量了材料的线性吸收光谱，研究了不同线性透射率的Ｃ６０／ＰＳｔ材料的反饱和吸收与光限幅特性．     

利用金刚石探测器测量软X光辐射功率

使用天然Ⅱａ型金刚石光电导探测器（ＰＣＤ），测量激光等离子体发射的软Ｘ光辐射。由于探测器在２００ｅＶ～２２００ｅＶ之间具有平响应特性，可以不加滤片直接测量Ｘ光功率和能量。金刚石ＰＣＤ与软Ｘ光能谱仪和平响应Ｘ光二级管的测量结果基本一致。     

激光散射研究聚甲基丙烯酸烷基磺酸钠／氯化钠水溶液的性质

本文用激光散射技术研究了具有不同长度烷基侧链的聚甲基丙烯酸烷基磺酸钠（ＰＳＳＲＭＡ）在０．１ＭＮａＣｌ水溶液中的性质。用静态光散射测定了这一系列聚合物的重均分子量Ｍ＿ｗ，均方半径Ｒ＿ｇ以及第二维利系数Ａ＿２．用动态光散射测定了光强的时间相关函数，运用Ｌａｐｌａｃｅ反演得到线宽分布Ｇ（Г）。当高聚物溶液的浓度大于１０￣（－３）ｇ／ｍＬ时，特性平均线宽〈Г〉迅速增加、表面张力降低；在２５℃－４７℃的范围内，〈Г〉随温度增加；烷基侧链越长，在０．１ＭＮａＣｌ水溶液中ＰＳＳＲＭＡ的分子排列更紧密。静态与动态光散射的结果建立以下方程：Ｄ＝ｋ＿ＤＭ￣ａ＿Ｄ，当α＿Ｄ～０．５６，对应于不同侧链，Ｋ＿Ｄ在１．５４×～１０￣（－４）－２．０７×１０￣（－４）（ｍＬ／ｇ）时，从线宽分布Ｇ（Г）得到ＰＳＳＲＭＡ的分子量分布。     

同步泵浦可调谐染料激光理论研究的进展

本文对近十几年来同步泵浦波长可调谐染料激光（ＳＰＤＬ）理论研究的进展情况进行了综述。文中提出了在目前阶段归纳总结ＳＰＤＬ理论研究成果和进一步进行此项工作的意义。在首先介绍了染料分子的较精颏的激光动力学模型之后，我们将对以往理论研究ＳＰＤＬ问题的三种主要方式进行详细的说明和比较。这三种方式分别为预选光脉冲包络的函数形式法。步进法和追踪法。虽然速率方程理论在绝大多数场合能够给出与实验定性吻合的结果。但     

强激光对星载光电探测系统的干扰与破坏研究

建立了激光辐照星载光电探测器的数学模型,对激光干扰和破坏星载光电系统的机理进行了研究,分析了激光光束与探测器光轴的偏角对干扰和破坏的影响.以CO2激光辐照HgCdTe探测器的实例,研究了强激光对探测单元的破坏,得到其损伤阈值曲线,并从理论上证明了强激光对星载光电探测系统干扰和破坏的可行性.     

Realization of high performance LDA-systems using optical amplifiers, high power semiconductor lasers and optical fiber lasers

Advanced novel techniques for sophisticated LDA applications are presented in this paper. By applying laser sources with high output powers like MOPA-lasers (master oscillator power amplifier), fiber lasers and booster fiber amplifiers to increase the laser power in the measuring volume and by amplifying the scattered light power with optical fiber preamplifiers to increase the sensitivity of the receiving units, the signal-to-noise-ratio of laser Doppler signals is drastically improved and the overall performance of a laser Doppler anemometer is significantly enhanced.     

Kinetics of I2 and HI photodissociation with implications in flame diagnostics

This paper investigates the application of iodine (I₂) tracer in reactive flows to image the concentration filed by using photodissociation spectroscopy (PDS). The PDS technique first uses a short laser pulse to completely photodissociate iodine-containing species into iodine atoms, and then uses a second laser pulse to image the iodine atoms. Due to the completeness and rapidity of the photodissociation (PD), the concentration of I atoms after PD represents that of the iodine element seeded into the flow, which forms a conserved scalar and can be used to image the concentration field. The feasibility of the PDS technique is evaluated in three steps. First, a multi-level kinetic model was developed to capture the major physics relevant to the PDS technique. Second, controlled experiments were conducted to validate the multi-level kinetic model. Third, the validated model was applied to evaluate the applicable range and accuracy of the PDS technique in representative hydrocarbon flames. The results suggest a simple approach to implement the PDS technique using I₂ seeding in flames, which can provide good accuracy across a wide range of mixture fractions and strain rates.     

激光激励下镝离子掺杂氟硼酸盐玻璃荧光体的辐照参数

采用高温熔融法制备了镝离子掺杂氟硼酸盐玻璃荧光体,利用积分球绝对光谱测试系统,在453 nm蓝色激光二极管激发下,对玻璃荧光体的荧光光谱进行表征,解析出玻璃荧光体的相关绝对荧光参量。测试与计算结果表明,1.0 Wt% Dy₂O₃掺杂玻璃荧光体在功率15.81 mW的蓝色激光激发下,净发射光谱功率是286.91 μW,发射光子数为17.17×1014 cps,其荧光量子产率达到25.86%。为提高玻璃荧光体对泵浦激光的利用率,减少残余激光成分,进而改善组合光品质,制备了大体积的1.5 Wt% Dy₂O₃掺杂玻璃荧光体,在高功率的蓝色激光激发下获得白色照明效果,该玻璃荧光体在激发功率分别为56.0和252.7 mW的激光激发下,组合荧光对应的色坐标分别是(0.316, 0.287)和(0.303,0.268)。激光激励下的高效白色发光表明Dy3+掺杂氟硼酸盐玻璃荧光体在激光照明领域具有良好的应用前景。     

Contrast-enhanced photothermal imaging for the evaluation of thermal transport parameters of liquids

In this article, we discuss the application of a baseline-suppressed, contrast-enhanced laser photothermal imager as a sensitive effusivity sensor for liquids, for the first time. We analyze the sources of errors associated with a conventional phase-comparison technique for evaluating the thermal transport parameters of liquids as a function of the pump power. Weak signal at lower powers and convection currents at higher powers are found to be the principal agencies deteriorating the sensitivity. Enhanced sensitivity has been achieved by using lower pump power and a signal baseline-suppressing common-mode-rejection-demodulation technique. The strength of thermoelastic vibration is small due to the low linear thermal expansion coefficient of the silicon nitride plate, which is the optical absorber. The approach has been extended for analyzing the effusivity modification of a water–methanol mixture as a function of methanol volume. The method is capable of detecting less than 1% change in effusivity for the mixture, which is 300–400% enhancement compared to the capability of conventional phase comparison. PACS 78.20.Nv; 81.70.Cv     

基于光纤光栅谐振腔的掺镱全光纤激光器设计(英文)

采用数值分析方法分析了光纤长度、后腔镜反射率等因素对激光器输出阈值泵浦功率、输出功率的影响,为全光纤激光器的优化设计提供了理论基础.在设计过程中采用光纤光栅作为光纤激光器的反馈与选频腔镜,通过锥度光纤实现了泵浦模块与掺镱双包层光纤之间的低损耗连接以及高效率的泵浦激光功率传输,成功研制了具备稳定窄化线宽激光输出的掺镱全光纤激光器.实验得到了波长峰值在1 082 .50 nm,谱线宽度0 .113 nm,最大输出功率8 .5 W,泵浦阈值功率0 .8 W,斜率效率为70 .8 %的稳定激光输出.     

适用于非常规工作环境中热释电型激光能量计的研制

现有的激光能量计传感器灵敏度系数都与其所处环境温度有关,在-50℃～70℃的温度范围内,灵敏度偏差较大,直接影响测量结果。为了达到消除环境温度的影响,采取在不同环境温度下对热释型能量计的灵敏度进行校准的研究方法。该校准方法与普通激光能量计的校准方法的不同之处在于对热释电型能量计进行校准时,温度由室温扩展到-50℃～70℃的温度范围。利用环境试验箱,每隔10℃固定一个温度点,进行激光能量的测量实验,得到各个温度点所对应的灵敏度修正系数,再借助最小二乘法建立起各个温度点上能量计灵敏度系数同环境温度的函数关系,从而实现了-50℃～70℃的温度范围内激光能量的准确计量。研制能直接工作于非常规工作环境下的热释电型激光能量计,对解决激光能量测量的外场需求有一定现实意义。     

Surface evolution and laser damage resistance of CO2 laser irradiated area of fused silica

A 10.6 μm CO₂ laser has been reported to effectively mitigate the laser damage growth of fused silica. Two zones of the laser irradiated area are defined in this work: the distorted zone and the laser affected zone. The parameters of the two zones are studied at different CO₂ laser beam sizes, irradiation times, and powers by microscopy, profilometry, and photoelastic method. The results show that the diameter of laser affected zone is almost completely determined by the laser beam size and the distorted zone is associated with the mitigation range of CO₂ laser beam. The diameter and depth of the distorted zone increase as the laser power and irradiation time increase. The depth grows exponentially depending on the irradiation time. The maximum residual stress discrepancy is located near the boundary of the laser affected zone. The laser damage resistance test results show that the distorted zone and the laser affected zone have a better damage resistance than the original substrate.     

遗传算法在激光器谐振腔优化设计中的应用

讨论了用遗传算法优化设计普通激光器谐振腔参量的方法.以典型的50 cm长的氦氖(He-Ne)激光器为例,进行了具体计算.结果表明:对于输出相同的激光功率,模拟优化的谐振腔参量与传统局域化设计(非优化)的结果基本一致.通过适当匹配谐振腔参量,仍可提高激光(单模)的输出功率.