Implementation of Laser Diode Characteristics Pulsed Testing by Time-resolved Technique

提出了一种基于时间分辨的脉冲式半导体激光器特性测试新方法,并研制了相应的测试系统。该方法根据脉冲驱动源的时序,同步产生采样窗口信号,然后根据采样窗采集半导体激光器的注入电流、端电压和输出光功率等数据,进而获得表征器件特性的曲线和参数。该方法解决了半导体激光器特性测试中的2个关键问题:一是现有的连续测试方法造成的器件温升,影响测试准确性和安全性;二是解决了脉冲驱动源与测试的同步问题。文中给出了最小脉冲宽度达100 nS的窄脉冲驱动的l-I-V测试曲线和测试参数。A new method to test pulsed laser diode characteristics based on time-resolved technique is presented,and the testing system is developed.Sampling window is made according to the timing of the pulsed current source.Using a synchronized sampling scheme,the injected current,the forward voltage and the optical output power are gathered,and then the curves and parameters are obtained.The rising of laser diode chip temperature under test is reduced,and the synchronization for pulsed current source and testing is resolved by this method.Based on the setup,L-I-V curves and related parameters of a laser diode were tested with pulsed injection of 100ns.国家“十一五”计量科研计划项目资助(J052009B002

A Fast Baseline Correction Method for Raman Spectroscopy Based on Comparison

拉曼光谱成像技术是基于拉曼散射效应所开发的一项现代检测技术,在现代生产、科学研究过程中使用非常广泛。拉曼光谱信号受荧光效应和仪器等方面的影响,往; 往会产生基线漂移,严重影响对信号特征的进一步提取。因此,必须对拉曼光谱信号进行基线校正。传统的基线校正方法,只针对单一光谱信号,计算量较大,在处; 理由大量拉曼信号组成的成像数据时,耗时较长且效果不佳。该文提出一种基于临近比较的快速基线校正方法,根据在相同背景下采集的光谱之间的相关性,实现快; 速基线校正,提高了拉曼成像数据的处理速度。Raman imaging is a kind of modern testing technology based on Raman; scattering,which has been widely applied in manufacturing and scientific; research. However, due to the fluorescent effect and instruments drift,; the baseline shift could easily occur, which has a strong impact on the; feature extraction of the Raman signals. Therefore,the baseline; correction is necessary and inevitable in the signal processing of Raman; spectra. The traditional baseline correction methods can only correct; the Raman spectrum one by one, so once a large amount of Raman imaging; signals have to be processed, the processing time is too long to accept.; In this paper, the baseline correction base on comparison which; considers the correlation between the Raman spectra and the same; background is proposed to realize the fast baseline correction and; improve the processing speed of Raman imaging data

基于匹配追踪的拉曼光谱信号重构算法

拉曼光谱技术是一种高灵敏度、无损伤、振动分子光谱技术,在医药、生物、分析化学等诸多领域有着重要的作用。然而,由于拉曼散射强度低,实际测得的拉曼信号容易被噪声所污染。特别是在较短的曝光时间,收集到的拉曼光谱的信噪比很低。因此,提出了一种基于匹配追踪算法的信号重构方法,用于提取低信噪比的拉曼信号。该方法首先通过阈值循环迭代的方法在平均谱上找出特征峰的位置、估计峰的区间。根据峰的位置区间等信息,用高斯密度函数生成字典。在噪声谱上,根据特征峰位置和区间,将其区分为有信号区间和无信号区间,在有信号区间上利用匹配追踪算法重构被噪声所掩盖的拉曼信号。该算法不仅能够很好的逼近掩盖在噪声中的拉曼信号,且在重构信号的过程中也会对基线进行扣除,无须作基线校正处理。在仿真和实验中对该算法与常规算法进行了比较,结果证明,该算法在低信噪比条件下能够较好的恢复拉曼信号。该算法不同于传统光谱去噪算法,能同时对拉曼光谱进行了基线扣除以及噪声的处理,且能取得较为理想的结果,不需要使用不同的算法对基线和噪声分别处理。其次,在算法上我们创造性地将匹配追踪算法用于拉曼光谱信号的稀疏逼近求解。国家自然科学基金项目(21503171)资

一种三维纳米定位台控制系统设计

这篇文章描述了一种三维纳米定位台控制系统。本系统采用双处理器架构,将ARM在逻辑控制、人机交互的优势同FPGA硬件可编程、并行处理的优势互补,再搭载自行设计的高精度ADC电路及DAC电路,完成了对三维纳米定位台的高精度运动控制

Design of CNC System for Wire Bending Robot Based on GTS Motion Controller

为了解决三维复杂金属线材和弹簧类零件的快速制造与生产问题,设计了一台具有X、z两个移动轴和y、A、b三个回转轴的五自由度弯丝机器人。采用PC+运动控制卡的开放式数控结构完成了系统硬件平台的搭建,利用MfC与控制卡提供的动态链接库完成了数控系统软件的编写,实现了系统的绝大部分功能,并应用于课题组设计的弯丝机器人系统中。In order to solve rapid manufacturing and processing problem of workpieces with 3D complex surface and springs w hich w ere made of metal w ire or such other materials,a five degreed of freedom CNC w ire bending robot w hich had X,Z tw o parallel movement axes and Y,A,B three rotary movement axes w as designed.The system hardw are platform w as build through an open-architecture NC system based on IPC and motion control card,the softw are w as programmed by Microsoft Foundation Class and the dynamic link library w hich provide by Googol GTS card that achieved mostly system functions.The CNC system has been used to the w ire bending robot w hich designed by research team.国家科技重大专项(2010ZX04001-162

Design of Raman spectroscopy measurement system based on shifted excitation method using two laser diodes with different wavelengths

拉曼光谱检测常常受到荧光干扰,而移频激发拉曼差分光谱法(SERDS)是一种有效抑制拉曼光谱荧光背景的方法。基于该方法,采用两个波长相近、基于体布拉格光栅技术的固定波长激光器,设计了一套拉曼光谱测试系统。通过控制激光器的功率和温度,保证了输出波长的稳定性。采用高灵敏度的薄型背照式面阵CCD,设计了光谱数据采集光路和电路。同时,在软件上实现了差分光谱的三种重构算法,即简单积分算法、带数值插值的简单积分算法和多重约束解卷积算法。在实验中,利用文中系统对强荧光背景的某品牌香油进行了拉曼光谱测量,分别采用这三种算法处理差分光谱进行光谱重构,并对比了重构效果。实验结果表明,设计的系统能够有效抑制荧光对拉曼光谱检测的影响。Raman detection is often disturbed by fluorescence background, while Shifted Excitation Raman Difference Spectroscopy(SERDS)is an effective method for fluorescent suppression on Raman spectroscopy.Based on this method, a Raman spectroscopy measurement system was designed using two closely space fixed-wavelength laser diodes stabilized with the Volume Bragg Gratings. The output wavelength of laser diodes was stabilized by manipulating their power and temperature. The light path and circuit of spectral data acquisition were designed with back-thinned area array CCD with high sensitivity. Besides, the three different reconstruction algorithms of the difference spectrum, namely simple integration algorithm, simple integration with data interpolation algorithm and multiple energy constraint iterative deconvolution algorithm could be realized through software of this system. The Raman spectra of sesame oil of some brand in the presence of a highly fluorescent were measured with this system and then the spectra reconstructed with three different algorithms to process the difference spectrum respectively were compared.Experimental results show that the system designed in this paper can effectively reject the effect of fluorescence to the Raman spectroscopy measurement.国家重大科学仪器设备开发专项(2011YQ03012417

基于主成分分析和多元曲线分辨的蓝细菌流式荧光光谱分析方法

利用流式细胞术对细胞进行多色荧光分析时,往往获得的是由多种组分荧光光谱混合的多元荧光光谱。在对蓝细菌进行光谱流式检测时,所测得的荧光光谱同时包含了多种未知荧光光谱,且存在严重的光谱混叠。为了获得蓝细菌中的主要组分光谱及其浓度,提出主成分分析和多元曲线分辨相结合的方法,对蓝细菌的流式荧光光谱进行处理。该方法通过主成分分析获得蓝细菌的主要纯组分数量,然后利用渐进因子分析寻找各组分的起始点和终止点,并估计纯组分的初始光谱,最后利用交替最小二乘结合其纯组分光谱的单峰性和非负性,对初始估计的纯组分光谱进行迭代修正,从而得到纯组分光谱及其组分浓度。仿真和实验结果表明,该方法能够准确地估计混合光谱中纯组分的个数并对其谱峰进行拟合,进而准确地估计各个组分的浓度。该方法不但适用于蓝细菌的光谱分析,还可用于其他多元混合光谱体系的解析。国家自然科学基金项目(21503171);;国家重大科研仪器研制项目(21627811)资

基于遗传算法的多组分光谱解析方法研究

光谱解析方法是一种常见的光谱分析方法,广泛用于各种化学计量学领域。现有的解析方法无法处理纯组分未知的应用体系,本文针对该情况,提出了基于遗传算法和最小二乘法的多元组分光谱解析定量分析方法。该方法首先通过遗传算法在混合光谱上寻找未知组分的最优峰位置和最优峰形,得到一组的最优纯组分光谱矩阵,再利用最小二乘拟合曲线,能够快速有效地解析混合光谱。在实验中,对纯组分光谱全未知、纯组分光谱部分未知及不同参数设置下算法的表现进行了讨论,分析其对算法收敛速度及计算结果精确性和稳定性的影响。利用该方法对流式细胞仪光谱数据进行处理,解析效果良好,谱线的契合程度高,验证其用于多组分流式细胞仪光谱数据分析的可行性、有效性和精确性。国家自然科学基金(NO.21503171);;国家重大科研仪器研制项目(NO.21627811

Optical System for Asymmetrical Crossed Czerny-Turner Raman Spectrometer with High Luminous Flux

为克服分立式便携拉曼光谱仪光通量低的缺点,设计了一种集拉曼探头光路与分光系统于一体的光学系统。探头光路采用大数值孔径的非球面透镜实现样品的有效激发和信号的高效收集,通过胶合透镜组缩小会聚光路尺寸、消除轴向色差。分光系统基于交叉非对称Czerny-Turner结构,为获得期望的光谱分辨率和光谱范围,建立了分光系统光谱分辨率及光谱范围与交叉非对称Czerny-Turner结构参数的关系。由测得的汞灯谱图可知,分光系统的光谱分辨率优于6 cm~(-1)(0.37 nm),光谱范围为790~950 nm(200~2000 cm~(-1))。将设计的光学系统对CCL4进行测试,实验结果表明在相同积分时间内由这种整体式的光学系统检测到的CCL4光谱谱峰强度是用商业探头通过光纤连接分光系统检测到的近3倍,验证了光学系统设计的合理性。To overcome the low luminous flux in separated portable Raman spectrometer, an optical system embodies the probe of Raman spectrometer and monochromator is designed. An aspherical lens with high numerical aperture is used to obtain the effective excitation of sample and the efficient collection of signal in the optical system of the probe. A cemented lens group is used to minish the size of converging path and eliminate chromatic aberration.The monochromator is based on asymmetrical crossed Czerny-Turner structure. For the purpose of achieving desired spectrum resolution and spectrum range, the relationship between the spectrum resolution and spectrum range of the monochromator and the structural parameters of the asymmetrical crossed Czerny-Turner system is established. According to the tested spectrogram of mercury lamp, the spectrum resolution of the monochromator is better than 6 cm~(-1)(0.37 nm), and spectrum range is 790~950 nm(200~2000 cm~(-1)). A sample of CCL4 is introduced to examine the performance of the optical system, the experimented results demonstrate that the peak intensity of spectrogram of CCL4 measured by this incorporative optical system is almost three times as high as that using a commercial probe couples to the monochromator, which verifies the rationality of the design of the optical system.国家自然科学基金(21503171);; 中央高校基本科研业务费项目(20720150091、20720150094);; 福建省高端装备制造协同创新中心资

Design of Raman spectroscopy measurement system based on SHINERS

基于壳层隔绝纳米粒子增强技术,开发了一种新型的等离激元拉曼光谱测试系统,该系统能够有效地提高被测物质的拉曼反射信号强度。壳层隔绝纳米粒子增强技术采用包裹了极薄的二氧化硅或者氧化铝壳层的单层金纳米粒子,能够产生较强的表面增强效应。整个测试系统的硬件部分主要包括双处理器(ArM和dSP)主控板、半导体激光光源、光谱仪、光纤探头和粒子施加装置;软件部分能够自动获取被测物质的拉曼谱图。这里,粒子施加装置用于自动地将壳层隔绝纳米粒子施加到被测样本中。在实验中,将测试系统用于检测食品违禁添加物三聚氰胺和孔雀石绿,以验证壳层隔绝纳米粒子增强拉曼光谱技术。实验结果表明,该测试系统具有较高的测试灵敏度和较短的测试时间,广泛地适用于食品安全中痕量物质快速检测。In this paper,the Raman spectroscopy mea surement system was presented,where Shell isolated Nanoparticle Enhanced Raman Spectroscopy(SHINERS) technique was used to amplify the Raman signal.This technique used gold nanoparticles coated with a thin,uniform,fully enclosed and optically transparent shell of silica or alumina so that the gold core generated a large surface enhancement.Based on this technique,the hardware framework of this measurement system was mainly composed of double central control chips(ARM and DSP),a laser diode source,a spectrometer,a fiber probe and a nanoparticle giving device;and the software of this system can achieve the Raman spectrogram automatically.The giving device was used to spread the SHINERS particle into the samples for improving automation.The experiments were performed to detect the food added melamine and malachite green for verifying the effectiveness of SHINERS.The results show that the measurement system is of high detection sensitivity and short testing time effectively,which can be widely adopted in the rapid detection of trace substances in food safety.国家重大科学仪器设备开发专项(2011YQ03012417