Real-time optical measuring system for dye colour and concentration-II. Dispersive dye

A real-time measuring method of a dispersive dye, i.e. oil dye, has been developed which enables us to measure the concentration and its fluctuation of the three base colours. The method is based on the light scattering theory and its principle requires three different lasers having the three base colours. The system consisted of a semiconductor laser and argon ion laser for light sources, a photodiode for a light detector and a personal computer for data processing. Detection sensitivity for the dye concentration was about 1 mg/l and was applicable for practical use.     

Real-time monitoring of structural vibration using spectral-domain optical coherence tomography

We report in this paper the development of a spectral-domain optical coherence vibration tomography (OCVT) using a broadband CCD-based spectrometer and a short-coherence white light source. We demonstrate that both the vibration amplitude and frequency can be quantified, in the frequency range 0-250 Hz, with an axial resolution of 1 μm. Furthermore, the inner structure (layer thickness) of a vibrating sample can also be quantified simultaneously. The developed OCVT is non-contact and noninvasive in nature, thus is ideal for real time and in situ monitoring of low-frequency micro-vibrations that have critical impacts on many high-precision manufacturing and engineering processes.     

Real-time surface figure monitoring of optical elements in continuous polishing

A real-time monitoring system is set up based on a computer, dynamic interferometer, beam expanding system,and a beam reflecting system. The stability and repeatability of the monitoring system is verified. A workpiece and a glass monitoring plate are placed in the same ring. The surface figure of the workpiece, monitored by the monitoring plate, synchronizes with the surface of the glass monitoring plate in terms of peak–valley and power.The influence of the reflection and transmission surface are discussed in theory and a numeral deviation in online and offline testing data is quantitatively analyzed. The new method provides a quick and easy real-time method to characterize changes to the optical surface during polishing.     

Noninvasive monitoring of glucose concentration with optical coherence tomography

We have proposed a tested in tissue phantoms and in vivo a novel sensor based on optical coherence tomography (OCT) for noninvasive and continuous monitoring of blood glucose concentration. OCT images were obtained from pig and rabbit skin before and after glucose administration. Slopes of OCT signals decreased substantially (~40% in tissues in vivo) and linearly with the increase of blood glucose concentration from 4 to 30 mM, typical for normal and diabetic subjects. Phantom studies demonstrated 1% accuracy of scattering-coefficient measurement. Our theoretical and experimental studies suggest that glucose concentration can potentially be measured noninvasively with high sensitivity and accuracy with OCT systems.     

宽光谱膜厚监控系统中光谱实时测量技术研究

 在宽光谱膜厚监控系统中,利用光栅光谱仪分光,线阵CCD接收,完成光谱的一次性快速扫描来控制膜层厚度,达到实时监控的要求。而系统光谱扫描的准确性,直接影响膜厚实时监控的有效性。为了得到准确的光谱信息,首先确定CCD像素和光波波长的对应关系,基于特征谱线的离散关系,采用最小二乘拟合法建立了光谱标定函数,经实验,标定波长均方根误差为0.037 nm;对于CCD实时输出的光谱监控信号,利用小波阈值优化算法抑制信号中的随机噪声,保留了光谱信号的细节成分,峰值误差的最大值为1.0%,峰位误差的最大值为0.3%,满足了监控中光谱分辨率的要求。     

大型环抛面形实时监测与控制

为解决大型激光驱动器建设中的关键工艺大型精密环形抛光技术一直存在着的控制困难、精度收敛不稳定的难题,分析了环形抛光加工中面形调整控制机理和本质,找到了传统调节控制和判断方法中的缺陷,提出了一种对环抛机面形变化基本实时的离线监测方法。这种监测方法具有结构简单、检测判断时间短和面形变化反应直观的优点。通过建立实验监测装置和实际加工验证,获得了较好的面形趋势判断和实时控制效果。     

非晶硅薄膜金属诱导晶化的实时监测系统与晶化效果测量

设计了用于测量非晶硅薄膜诱导晶化的电阻值的实验装置,通过实时电阻测量方法实现了金属诱导晶化制备多晶硅薄膜的实时监控.结果表明薄膜的电阻值在高温下随晶化时间呈指数衰减,且具有很强的温度依赖关系.采用品粒边界势垒模型解释了阻值衰减行为,分析计算了样品的阻值衰减规律.应用拉曼光谱分析检测实时电阻测量的可靠性,结果表明实时电阻测量方法可以用于金属诱导晶化动力学的研究.     

大型环抛面形实时监测与控制

为解决大型激光驱动器建设中的关键工艺大型精密环形抛光技术一直存在着的控制困难、精度收敛不稳定的难题,分析了环形抛光加工中面形调整控制机理和本质,找到了传统调节控制和判断方法中的缺陷,提出了一种对环抛机面形变化基本实时的离线监测方法。这种监测方法具有结构简单、检测判断时间短和面形变化反应直观的优点。通过建立实验监测装置和实际加工验证,获得了较好的面形趋势判断和实时控制效果。     

激光器用高频调制射频激励源的实时监测系统

介绍了基于C8051F023单片机的高速数据采集系统的设计,在LABVIEW环境下实现数据处理和分析系统的设计。两者通过串口结合能实现对射频激励源入射和反射信号的电压值、功率值、频率、占空比等参数实时监测。     

Simultaneous optical coherence tomography--Indocyanine Green dye fluorescence imaging system for investigations of the eye's fundus

We have developed a dual-channel optical coherence tomography-Indocyanine Green dye (OCT-ICG) fluorescence system based on a previously reported ophthalmic OCT confocal imaging system. The confocal channel is tuned to the fluorescence wavelength range of the ICG, and light from the same optical source is used to generate the OCT image and to excite the ICG fluorescence. The system enables the clinician to visualize simultaneously en face OCT slices and corresponding ICG angiograms of the ocular fundus, displayed side by side. C-scan (constant depth) and B-scan (cross section) images are collected by a fast en face scan (T scan). The pixel-to-pixel correspondence between the OCT and angiography images allows the user to capture OCT B scans precisely at selected points on the ICG confocal images.     

微球动态涂敷状态实时监测光学系统的设计

介绍了一种可用于实时监测直径0.2～1.0 mm激光核聚变靶球涂敷状态的光学系统的设计,系统采用环形LED照明系统以适合特殊的照明要求,用Petzval型物镜使500 mm处的微球清晰成像于CCD像面上,CCD输出的图像电信号经图像采集卡转换成数字信号,最后该数字信号由计算机进行处理,实现了系统对靶球膜层涂敷作业的自动监控,大大提高了涂敷效率。所设计的系统轴上点最大弥散斑直径为12.6 mm,轴外最大弥散斑直径为15.8 mm,整个视场的像质比较均匀,分辨率较高,对于波长522 nm的光线,场曲和畸变分别小于15 mm和0.012%,像质优良。     

微球动态涂敷状态实时监测光学系统的设计

 介绍了一种可用于实时监测直径0.2～1.0 mm激光核聚变靶球涂敷状态的光学系统的设计,系统采用环形LED照明系统以适合特殊的照明要求,用Petzval型物镜使500 mm处的微球清晰成像于CCD像面上,CCD输出的图像电信号经图像采集卡转换成数字信号,最后该数字信号由计算机进行处理,实现了系统对靶球膜层涂敷作业的自动监控,大大提高了涂敷效率。所设计的系统轴上点最大弥散斑直径为12.6 mm,轴外最大弥散斑直径为15.8 mm,整个视场的像质比较均匀,分辨率较高,对于波长522 nm的光线,场曲和畸变分别小于15 mm和0.012%,像质优良。     

基于EPICS 的HL-2A 装置实时监测和报警系统

分析了HL-2A 实验中可能存在的各种故障问题,设计并开发了一种基于EPICS 网络的实时监测和报警系统。通过SNMP 协议,以EPICS 网络为基础,进行全域的消息监控及实时报警。实现了有效监控实验运行过程中整个IT 系统、控制系统、采集主机等异常情况,并实时进行电话报警、短信报警、邮件报警,有效解决了实验中遇到的各种故障监测及可能引发的问题。     

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分析了HL-2A实验中可能存在的各种故障问题,设计并开发了一种基于EPICS网络的实时监测和报警系统。通过 SNMP 协议,以 EPICS 网络为基础,进行全域的消息监控及实时报警。实现了有效监控实验运行过程中整个 IT 系统、控制系统、采集主机等异常情况,并实时进行电话报警、短信报警、邮件报警,有效解决了实验中遇到的各种故障监测及可能引发的问题。     

Real-time Ginzburg-Landau theory for bosons in optical lattices

Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for the Bose-Hubbard model which describes the real-time dynamics of the complex order parameter field. Analyzing the excitations in the vicinity of the quantum phase transitions it turns out that particle/hole dispersions in the Mott phase map continuously onto corresponding amplitude/phase excitations in the superfluid phase. Furthermore, in the superfluid phase we find a sound mode, which is in accordance with recent Bragg spectroscopy measurements in the Bogoliubov regime, as well as an additional gapped mode, which seems to have been detected via lattice modulation.     

Real-time detection technique for Doppler optical coherence tomography

We propose and demonstrate a novel detection technique, based on a modified electronic phase-locked loop, for Doppler optical coherence tomography. The technique permits real-time simultaneous reflectivity and continuous, bidirectional velocity mapping in turbid media over a wide velocity range with minimal sensitivity penalty compared with conventional optical coherence tomography, which is a major advance over current postprocessing and discrete parallel detection techniques.     

井下光纤微地震监测系统设计及应用

为满足油气开发中微地震监测的需求,基于时分复用方案设计了一种新型井下3分量光纤微地震监测系统。结合室内测试,该系统本底噪声小于−101 dB,动态范围大于120 dB,级间串扰小于−67 dB,满足微地震信号探测的需求。该系统已成功应用于新疆油田水力压裂微地震现场探测。监测结果表明:该系统可清晰捕捉微地震的P波、S波信号,较好地揭示了水力压裂微地震信号的特征信息,为微地震事件的空间定位和裂缝特征参数解释建立了良好基础。     

An optical system for monitoring torsion in a power transmission shaft in realtime

An optical system has been proposed and verified experimentally for monitoring the torsion of a power transmission shaft in realtime. The system consists of a pair of lasers, mirrors and light receivers as a sensor head, and logic circuit, high-frequency oscillator, and computer as a data processing system. The smallest measurable angle of torsion can be expressed by ω/f, where ω is the rotational frequency of the power transmission shaft and f is the frequency of the oscillator. The experimental error was found to be a few percentage points.     

Nonlinear optical frequency-mixing in dye vapors

Application of gas-phase molecular substances in nonlinear optics appears very promising. The paper reports on the experimental two-photon-resonant four-wave frequency-mixing of Nd: YAG laser radiation inp-terphenyl (PTP) vapors. The nonlinear susceptibility calculated from the experimental data made ⁽³⁾10^–31 ESU. This value is commensurable with the quasiresonant susceptibility of alkali atoms and is considerably higher than the resonant susceptibilities of simple molecules such as NO and CO. The paper seems to be the first devoted to the nonlinear frequency-mixing in dye vapors.     

Spectral imaging system for non-contact colour measurement

This paper describes the development of a non-contact system for measuring colour of printed material at web speeds. The system proposed uses a non-contact spectrophotometer based on a holographic grating, in conjunction with a conventional monochrome area scan camera, from which colour spectral data is extracted, whilst a xenon flash is used to illuminate colour samples. Software and hardware details of the system are given, along with the underlying mathematics for colour space conversion and measurement. Conversion equations from X, Y, Z chromaticity co-ordinates to the RGB system are presented, and also equations to convert from the L^*a^*b^* colour space to X, Y, Z chromaticity co-ordinates. Experimental results are presented whereby the non-contact spectral system is shown to perform to a colour tolerance exceeding that of conventional colour video systems.