基于法布里-珀罗标准具的532 nm多普勒测风激光雷达系统设计和分析

 设计了采用532 nm 种子注入稳频钇铝石榴石（YAG）激光器作为辐射源的基于四通道法布里-珀罗标准具的瑞利和米散射测风激光雷达系统。介绍了激光雷达的多普勒测量基本原理;给出了雷达系统的主要参数,重点对基于分子后向散射信号的外侧双通道标准具的带宽、自由谱间距、峰值间距等指标进行了详细设计与分析,确定了内侧双通道标准具参数;对全系统速度灵敏度、信噪比与探测距离的关系进行了理论模拟。结果表明,可以实现从边界层至对流层高低空一体化探测。     

Mobile Rayleigh Doppler wind lidar based on double-edge technique

<正>We describe a mobile molecular Doppler wind lidar(DWL) based on double-edge technique for wind measurement of altitudes ranging from 10 to 40 km.A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity.The lidar operates at 355 nm with a 45-cm-aperture telescope and a matching azimuth-over-elevation scanner that provides full hemispherical pointing.To guarantee wind accuracy,a single servo loop is used to monitor the outgoing laser frequency to remove inaccuracies due to the frequency drift of the laser or the etalon.The standard deviation of the outgoing laser frequency drift is 6.18 MHz and the corresponding velocity error is 1.11 m/s.The wind profiles measured by the DWL are in good agreement with the results of the wind profile radar(WPR).Evaluation is achieved by comparing at altitudes from 2 to 8 km.The relative error of horizontal wind speed is from 0.8 to 1.8 m/s in the compared ranges.The wind accuracy is less than 6 m/s at 40 km and 3 m/s at 10 km.     

福建寿山黑田与坑头黑的谱学与矿物学研究

寿山石是我国国石候选石之一,也是四大图章石之首。寿山石中黑田为黑色田黄石,是田黄中的特殊品种,产于寿山溪两旁的田地中。母源区坑头占的位置产有黑色坑头石。本文将黑田与母源区的黑色坑头石(坑头黑)进行对比研究,采用X射线粉晶衍射(XRD)、红外吸收光谱(IR)、激光剥蚀等离子质谱仪(LA-ICP-MS)和扫描电镜(SEM)对它们的矿物成分、红外吸收峰特征、颜色成因以及矿物的微区形貌特征进行对比研究。测试结果显示,黑田与坑头黑的矿物成分不同,红外光谱和X射线粉晶衍射分析表明坑头黑以地开石为主;另外,X射线粉晶衍射分析表明坑头黑中可含有杂质矿物如叶蜡石、伊利石、黄铁矿和石英。而红外光谱和X射线粉晶衍射分析表明黑田的主要成分为地开石或者珍珠陶石;另外,X射线粉晶衍射分析表明黑田中含有少量的硫磷铝锶矿和镁硫铁矿。黑田与坑头黑的矿物微形貌也存在差异,黑田矿物晶粒大小不一致、片状晶体颗粒边缘圆化,说明黑田中矿物晶体曾遭受过水岩反应的溶蚀改造作用。而坑头黑中地开石结晶程度良好,晶粒呈片状,边棱尖锐,晶体颗粒大小较为一致,说明坑头黑为原生矿。根据LA-ICP-MS微量化学成分分析测试,初步认为黑田与坑头黑的黑色皆与Fe元素致色有关,该结论有待进一步测试研究。     

Compensation of chromatic dispersion for full-duplex ROF link with vector signal transmission using an optical phase shifter

We demonstrate the theory of chromatic dispersion(CD)-induced constellation rotation(CR) in a radio-over-fiber(ROF) link and a method for compensation. We also propose a 60 GHz full-duplex ROF system with vector signal transmission including no CD effect. The evaluation of 5 Gb/s 16 quadrature amplitude modulation signal transmission shows that the CD-induced CR can be entirely overcome due to the proposed method which is simply implemented through an optical phase shifter. The proposed ROF schedule is not only applicable for V-band(57–64 GHz) but also fits for W-band(75–110 GHz), or any other bandwidth.     

Analysis of Detectors and Transmission Curve Correction of Mobile Rayleigh Doppler Wind Lidar

A mobile molecular Doppler wind lidar （DWL） based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity. The lidar operates at 355 nm with a 45-cm aperture telescope and a matching azimuth-over-elevation scanner that can provide full hemispherical pointing. In order to guarantee the wind accuracy, different forms of calibration function of detectors in different count rates response range would be especially valuable. The accuracy of wind velocity iteration is improved greatly because of application of the calibration function of linearity at the ultra low light intensity especially at altitudes from 10 km to 40 km. The calibration functions of nonlinearity make the transmission of edge channel 1 and edge channel 2 increase 38.9% and 27.7% at about 1 M count rates, respectively. The dynamic range of wind field measurement may also be extended because of consideration of the response function of detectors in their all possible operating range.