棱镜型光热偏振光谱法

提出了一种高灵敏度的棱镜型光热偏转光谱法,给出了系统的理论分析,导出了由泵浦光引起的探测光的偏向角表达式.并与普通型光热偏转技术作了比较,理论分析结果表明,棱镜型光热偏转检测方法比普通型光热偏转技术具有更高的灵敏度.     

光热偏转成像实验

概述了光热偏转成像原理,搭建了热波成像光热偏转自动化检测系统,并实现了数据采集和数据处理的自动化.利用该实验系统绘制了直线划痕SrBT样品和三角划痕硅片样品的表面光热偏转图,成像结果清晰直观.     

光学薄膜的光热偏转信号分析

本文给出了透明基体上的单层薄膜在激光辐照下的温度分布和光热形变偏转信号的理论表达式。通过数值计算,分析了偏转信号与薄膜参数、基体参数以及调制频率之间的关系,用反射式光热偏转装置对光学薄膜的光热偏转信号进行了实验研究。结果表明,理论计算和实验结果是一致的。     

用共线光热偏转技术测量光学薄膜的微弱吸收

用具有高灵敏的共线光热偏转技术研究SiO_2、ZrO_2、MgF_2、ZnS等单层光学薄膜的吸收特性,测得它们的吸收率.实验结果与激光量热法及横向光热偏转技术符合良好,表明共线光热偏转技术是测量光学薄膜弱吸收的较理想方法.     

利用激光光热技术研究钛酸钡材料的导热性能

利用激光光热偏转技术测量了钛酸钡材料的热扩散率。根据所测量材料的光热光偏转信号,通过最小二乘法中的非线性拟合,直接拟合出了材料的热扩散率,克服了光热偏转技术中“Mirage effect”步骤多、计算复杂、误差大的缺点。测量了在不同成型压力和不同烧结温度下钛酸钡材料的热扩散率,得到了热扩散率随成型压力和烧结温度的变化规律。对实验结果进行了分析和讨论。     

光热偏转检测技术自动测量的研究

介绍了光热偏转技术自动测量材料热物性的原理及实验方法。根据光热偏转检测理论建立了一套自动检测系统,从自动控制、数据采集和数据处理等方面实现了光热偏转检测技术的自动化测量。设计出了步进电机自动控制和数据处理软件。利用该系统对钛酸锶钡材料的热扩散率进行了测量,发现随着掺杂量铈的增加,钛酸锶钡的热扩散率逐渐减小,当掺杂量铈增加到一定值时,其热扩散率又开始增加。     

脉冲光热光束偏转测定导温系数

从理论上推导了脉冲光热光束偏转瞬态信号与导温系数关系,表明可由脉冲光热光束偏转信号测定热物性的重要参数之一——导温系数。实验上测量了蒸馏水、有机玻璃、光学玻璃的导温系数。本方法的特点是非接触瞬态测定。     

激光光热偏转成象法无损检测光学薄膜的激光损伤

介绍了应用激光光热偏转成象法无损检测光学薄膜激光损伤的基本原理，由此建立了实验检测装置，对光学薄膜表面的激光损伤进行了扫描检测，并以直观的灰度象显示. 实验结果证明了激光光热偏转成象法检测光学薄膜激光损伤具有直观、有效、可确定损伤阈值的优点.     

光学薄膜热膨胀系数的研究

光热位移偏转技术结合横向光热偏转技术可用于研究薄膜样品的热膨胀系数.本文以SiO_2、TiO_2、ZrO_2、MgF_2、ThF4等单层光学薄膜为例.报道相关的实验方法及实验结果.     

基于LabVIEW的光热偏转检测系统的设计

将虚拟仪器技术和光热偏转检测技术相结合,在LabVIEW平台上设计开发了一套材料热扩散率测量的自动扫描和数据处理系统。整个系统在仪器控制、数据采集和数据显示等方面实现了自动化测量,并且集成了光热偏转检测技术的数据处理功能。实验结果表明系统运行稳定,操作简单快捷,具有很好的实时性和直观性。     

An investigation of the photothermal deflection spectroscopy technique for temperature measurements in a flame

The technique of photothermal deflection spectroscopy (PTDS) is investigated for temperature measurements in a flame. The spatial distribution of temperature is measured in two different types of burners operating with methane and oxygen, and methane and air. The spatial distributions of the temperature are in qualitative agreement with our expectations. At two points, the temperatures measured by PTDS have been compared with those measured by Boltzmann distributions. The measurements agree within their uncertainties. All the effects that affect the reliability of this technique are investigated and discussed. Finally, the pros and cons of the PTDS technique for temperature measurement are discussed. Received: 31 January 2002 / Published online: 8 August 2002     

Theory of two-photon photothermal deflection spectroscopy in stationary and flowing media for arbitrary optical pulse length

A general theory of pulsed two-photon photothermal deflection spectroscopy (PTDS) is presented. We find that there are significant enough differences in the amplitude and temporal evolution of PTDS signals between the results of the single- and two-photon theories that if one tries to interpret two-photon data with single-photon theory, the extracted values may be considerably in error. Our theory is sufficiently general that it incorporates both stationary and flowing media and considers optical pulses of arbitrary length. Moreover, the temporal profile of the optical pulse is explicitly taken into account. The two-photon absorption coefficient is explicitly expressed in terms of oscillator strengths and Clebsch–Gordan coefficients, and the Doppler width for both co-propagating and counter-propagating beams is taken into account. Although the theory is primarily developed for atomic and molecular vapors, it can easily be adapted for condensed matter by expressing the absorption coefficient in terms of the properties of the liquid or solid under investigation. PACS 82.80.Kq; 42.62.Fi; 39.30.+w     

Kinetics of subnanometer displacements of solid surfaces under local heating by a laser pulse

A method with space-time resolution Δr∼ μm and δt∼0.1 μs is proposed for investigating the kinetics of angstrom-size displacements and deformations induced on solid surfaces by local irradiation with a laser pulse. The instantaneous deformation profiles were recorded at a set of points on the surface on micron-size scales by the method of photothermal deformation of the surface (PTDS) according to the kinetics of the deflection of a probe laser beam followed by extraction of data corresponding to the same moment in time; the instantaneous displacement profiles were obtained by integrating the instantaneous deformation profiles numerically in the radial direction. Instantaneous profiles obtained in this manner for angstrom-scale deformations and displacements are presented for a number of metal samples. The nature of the kinetic displacements obtained at the center of an ∼10–100 μm heating laser spot is discussed. Zh. Tekh. Fiz. 67, 105–109 (February 1997)     

两类喇曼光纤放大器的研究

以Photonic Transmission Design Suite(PTDS)仿真试验平台为基础，对单信道40Gb／s光纤传输系统中的两类RFA进行了研究和比较，并对各自系统进行了优化．最后指出，现有的依赖DCF进行色散补偿的方法在40Gb／s光纤传输系统中不再适用．     

S波段宽带光纤喇曼放大器研究

在PTDS(Photonic Transmission Design Suite)仿真平台上,用3个泵浦源的RFA实现了S波段的增益平坦,同时对泵浦光与信号光,信号光与信号光,泵浦光与泵浦光之间的相互作用以及RFA的噪声特性进行了研究.     

基于半导体光放大器交叉增益调制(SOA-XGM)波长变换器仿真研究

本文在PTDS(Photonic Transimission Design Suite)软件仿真平台上对基于半导体光放大器交叉增益调制(SOA-XGM)的波长变换器的变换特性作了仿真实验研究,仿真并分析了输入信号光功率、输入探测光功率、偏置电流和SOA的结构参量等因素对变换信号的消光比(ER)、Q值及误码率(BER)的影响关系.研究结果对优化设计SOA-XGM波长变换器有一定的参考价值.     

10Gb/s单信道光纤传输系统性能仿真研究

光纤传输系统的优化设计是光纤通信质量的重要保证.本文基于光子传输设计套件(PTDS)软件平台,对光纤传输系统的传输特性作了大量仿真研究,并得出分析了一些重要参量如光纤长度,光纤的损耗和衰减,光功率大小等对光传输系统的影响规律,给出了相应的补偿措施.本文研究结果对优化光纤传输系统有一定的参考价值.     

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为EAST装置中性束注入器设计了一套用于将剩余离子在线电偏转的结构,并对系统各设备的核心参数进行了估算。在4.41kV偏转电压作用下,该电偏转系统可提供80keV氘离子束偏转所需的偏转电场。在偏转电场调制情况下,该电偏转系统可有效降低极板表面的热负荷,进而满足EAST中性束注入器稳态运行的需要。     

中性束注入器电偏转系统的参数设计与估算研究

为EAST 装置中性束注入器设计了一套用于将剩余离子在线电偏转的结构,并对系统各设备的核心参数进行了估算。在4.41kV 偏转电压作用下,该电偏转系统可提供80keV 氘离子束偏转所需的偏转电场。在偏转电场调制情况下,该电偏转系统可有效降低极板表面的热负荷,进而满足EAST 中性束注入器稳态运行的需要。     

EAST-NBI磁偏转系统束传输特性模拟研究

根据EAST-NBI偏转系统工作原理,分析了束流在偏转系统传输的基本过程和特点。利用直接蒙特卡罗方法,发展了中性束注入器束偏转区域束流传输模拟程序。结果显示:EAST-NBI磁偏转系统可很好地剥离束流中的剩余离子;束偏转区域束流再电离损失约为2.43%;束流180°偏转所带来线聚焦过程使偏转磁体磁极护板局部面临较高的热流密度。