探测器横纹误差对大孔径静态干涉成像光谱仪影响的建模与修正

大孔径静态干涉成像光谱技术在航天遥感应用中,由于探测器横纹误差影响,使获得的干涉数据无法反演光谱数据,需要对横纹误差进行修正。通过对干涉成像机理的分析,给出探测器横纹误差影响下的干涉成像模型,提出横纹误差影响下干涉数据修正方法。最后利用仪器获取的数据,对提出的修正方法进行验证,由处理结果可以看出,本文所提的修正方法可以很好的修正横纹误差对光谱的影响,提高反演光谱的精度。     

迈克尔逊干涉仪实验中系统误差的发现及处理

改变传统观念,重视系统误差的发现及处理,培养发现问题、解决问题的能力。     

反相电极聚合物定向耦合电光开关的优化设计

为了消除单节电极定向耦合电光开关的工艺误差对器件性能的不良影响,应用耦合模理论、电光调制理论、保角变换及镜像法,优化设计了一种两节交替反相电极聚合物定向耦合电光开关.模拟结果表明,该器件具有良好的开关性能:在1 550 nm的工作波长下,器件耦合区的长度为4 753.5 μm,交叉态电压为1.22 V,直通态电压为2.65 V,插入损耗小于2.21 dB,串扰小于-30 dB.通过微调状态电压,可以很容易地消除工艺误差对器件性能产生的不良影响.本文方法的设计结果与光束传播法的仿真结果符合得很好.     

A diode laser spectrometer at 634nm and absolute frequency measurements using optical frequency comb

This paper reports that two identical external-cavity-diode-laser (ECDL) based spectrometers are constructed at 634 nm referencing on the hyperfine B-X transition R(80)8-4 of ¹²⁷I₂. The lasers are stabilized on the Doppler-free absorption signals using the third-harmonic detection technique. The instability of the stabilized laser is measured to be 2.8×10^-12 (after 1000 s) by counting the beat note between the two lasers. The absolute optical frequency of the transition is, for the first time, determined to be 472851936189.5 kHz by using an optical frequency comb referenced on the microwave caesium atomic clock. The uncertainty of the measurement is less than 4.9 kHz.     

基于单次旋转的旋转非对称面形误差绝对检测技术研究

绝对检测技术是剔除干涉仪系统误差进而提高面形检测精度的有效手段。基于单次旋转的绝对检测技术由被测球面绕光轴旋转前后的检测数据,采用基于最小二乘法的Zernike多项式拟合,剔除系统误差,获得被测面的旋转非对称面形误差。详细推导了理论计算公式,分析了单次旋转角度对算法检测精度的影响,并和多次旋转法作了对比,其残差均方根(RMS)值约为1.5nm。该方法只需一次旋转两次检测,在保证检测精度的同时简化了检测过程。     

M-ary information processing via an optimal nonlinear detector

This paper presents a novel approach of M-ary baseband pulse amplitude modulated signal processing via a parameter-optimized nonlinear dynamic system.This nonlinear system usually shows the phenomenon of stochastic resonance by adding noise.To thoroughly discuss the signal processing performance of the nonlinear system,we tune the system parameters to obtain a nonlinear detector with optimal performance.For characterizing the output of the nonlinear system,the derivation of the probability of detection error is given by the system response speed and the probability density function of the nonlinear system output.By varying the noise intensity with fixed system parameters,the phenomenon of stochastic resonance is shown and by tuning the system parameters with fixed noise,the probability of detection error is minimized and the nonlinear system is optimized.The detection performance of the two cases is compared with the theoretical probability of detection error,which is validated by numerical simulation.     

光学材料光学均匀性的波长调谐两步绝对测量法

光学均匀性是光学材料的重要指标,目前高精度的测量方法一般采用绝对测量法,而该方法步骤繁琐,容易受环境影响。根据波长移相干涉仪的移相特点,提出了测量光学材料光学均匀性的波长调谐两步绝对测量法。该方法在波长移相干涉仪中通过平行平板放入测量和空腔测量两个步骤得到平行平板的光学均匀性。在模拟仿真验证方法的正确性后,进行了实验研究,并与传统的绝对测量法的测量结果进行比较。结果表明,波长调谐两步绝对测量法可用于测量平行平板的光学均匀性,且测量步骤简单,精度较高。     

Stereochemical analysis of ferrocene and the uncertainty of fluorescence XAFS data

Methods for the quantification of statistically valid measures of the uncertainties associated with X‐ray absorption fine structure (XAFS) data obtained from dilute solutions using fluorescence measurements are developed. Experimental data obtained from 10 mM solutions of the organometallic compound ferrocene, Fe(C₅H₅)₂, are analysed within this framework and, following correction for various electronic and geometrical factors, give robust estimates of the standard errors of the individual measurements. The reliability of the refinement statistics of standard current XAFS structure approaches that do not include propagation of experimental uncertainties to assess subtle structural distortions is assessed in terms of refinements obtained for the staggered and eclipsed conformations of the C₅H₅ rings of ferrocene. Standard approaches (XFIT, IFEFFIT) give refinement statistics that appear to show strong, but opposite, preferences for the different conformations. Incorporation of experimental uncertainties into an IFEFFIT‐like analysis yield refinement statistics for the staggered and eclipsed forms of ferrocene which show a far more realistic preference for the eclipsed form which accurately reflects the reliability of the analysis. Moreover, the more strongly founded estimates of the refined parameter uncertainties allow more direct comparison with those obtained by other techniques. These XAFS‐based estimates of the bond distances have accuracies comparable with those obtained using single‐crystal diffraction techniques and are superior in terms of their use in comparisons of experimental and computed structures.     

Line Intensity of R(0) and R(3) of the CH4 2ν3 Band from Diode Laser Spectroscopy

We have determined the spectroscopic parameters that are necessary to describe accurately the R(0) line profile of the CH₄ 2ν₃ band from about 1 Torr to a few hundred Torr of pure CH₄. The intensities determined at each pressure are in overall agreement to better than 0.7%. The R(3) manifold of the same band has also been investigated. Relative positions and absolute intensities of the three transitions composing the triplet have been determined. The intensity distribution inside the triplet is in fair agreement with recent theoretical predictions.     

小型轻便式流速仪检定系统设计

为满足FP系列流速仪的计量检定需求,提出了一种小型便携式流速仪检定系统的设计方案。根据匀速运动时间等约束条件确定了环形水槽的几何参数。采用FPGA和上位机作为数据处理和控制核心,实现了对伺服电机转速的精确控制。设计了光电编码器和无线摄像机与上位机之间的通信方式,实现了检定装置标准流速值和被检仪器示值的数据读取。对测试数据的处理方法和测控软件的结构框架进行了分析。同时,对实验装置的测量误差进行了分析。结果表明,标准流速值的扩展不确定度为1.28×10-3m/s,检定装置符合量值传递要求,可作为FP系列流速仪计量检定的标准装置。