标准线纹尺检定中的数字图像处理技术

为符合实际应用,通过卷积算子识别双边缘,进而计算线纹中心.在此基础上,利用标准线纹模板和激光干涉仪对像素大小进行全幅面标定,根据干涉仪标定结果,直接测量三等标准金属线纹尺,或者对瞄准进行补偿.实验表明,数字图像处理技术在标准线纹尺检定中有很高的应用价值.     

两米光栅——线纹自动测量仪（一）

描述了一台能够对长度达１ｍ的线纹尺和长度达２ｍ的光栅尺（线位移传感器）进行测量的激光干涉仪，干涉仪设计成了双干涉光路系统，以消除光栅尺安装引入的阿贝误差，这台测量仪采用干涉条纹计量原理，对光栅尺和线纹尺的线值精度进行检测，并能对光机信号的质量进行评价。测量过程中，对空气折射率实现了实时修正。     

一种基于全自动线纹尺检定仪的π尺示值误差校准方法探索

本文阐述了使用全自动线纹尺检定仪进行π尺示值误差校准的原理和方法,并比较了用全自动线纹尺检定仪、标准钢卷尺及激光干涉仪进行π尺示值误差校准的异同.实验结果证明,该测量方法操作简单、精度高、测量结果准确可靠.     

线纹尺安装方式对空气折射率实时修正效果的影响

根据三种实际测量情况进行分析,介绍了在使用激光干涉法测量线纹尺过程中,空气折射率实时修正技术对测量结果的影响与仪器布局和线纹尺安装方式的关系,并得出了相应的结论.     

空间大尺寸坐标测量校准装置

空间大尺寸坐标测量校准装置主要用于激光干涉仪、线纹尺等的长度精度校准以及激光跟踪仪、经纬仪坐标测量系统等可移动式空间大尺寸坐标测量系统的直接坐标比对和校准.对该装置的组成及工作原理进行介绍的基础上,阐述了校准装置的应用过程,并对该装置的测量不确定度进行了分析.     

CCD用于高精度线纹分划检测系统的研究

本文介绍一种用线阵ＣＣＤ作为图象传感器实现对条码型水准尺线纹发划精度的检测系统,叙述了以ＣＣＤ、图象数字信号采集与处理接口电路、双频激光干涉仪为核心的高精度动态位移测量的原理与实现的方法。     

三等标准金属线纹尺的测量不确定度

本文介绍了双频激光干涉仪检定三等标准金属线纹尺其检测结果的不确定度分析方法。     

影响三等金属线纹尺测量结果准确度因素的探讨

三等金属线纹尺主要用于检定水准标尺、钢直尺以及准确度较低的线纹尺。目前,使用中的线纹尺多由黄铜、锌白铜、不锈钢等材料制成。在传统检定中,多采用与二等金属线纹尺进行比较的测量方法。随着科技的发展,激光越来越多地被应用在线纹尺的检定中。根据标准器选取和测量方式的不同,线纹尺的检定方法可分为两种形式:以激光干     

基于摄影测量的基准尺长度测量系统的调节与误差分析

基准尺作为摄影测量长度基准,其精度直接影响测量结果的准确性,为了保证基准尺长度的测量精度,设计了由气体静压导轨、激光干涉仪、CCD成像系统组成的测量系统。分析了影响测量精度的因素,并对组成基准尺的标志圆成像位置、CCD相机光轴、激光干涉仪、基准尺和CCD成像系统绕自身光轴旋转的调节误差进行了计算分析,用于指导CCD成像系统、激光干涉仪和基准尺的调节。最后应用该系统对基准尺进行多次测量,结果表明基准尺长度测量的标准差可达到1 μm,满足工业摄影测量的要求。     

多功能线纹尺自动测量装置研制

针对目前标准钢卷尺、铟瓦水准标尺、数字水准仪条码尺测量过程中遇到的问题,基于激光干涉测长和图像处理技术对线纹间隔进行测量的原理,研制开发出了多功能线纹尺自动测量装置.探讨了数字水准仪条码尺的解码机理,分析了条码尺的编码图,对各公司生产的条码尺给出了校准方法,评估了整套装置的测量不确定度.实践证明,该装置能对多种高准确度的线纹计量器具进行有效检测.     

Shot noise in gravitational-wave detectors with Fabry-Perot arms

Shot-noise-limited sensitivity is calculated for gravitational-wave interferometers with Fabry-Perot arms, similar to those being installed at the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Italian-French Laser Interferometer Collaboration (VIRGO) facility. This calculation includes the effect of nonstationary shot noise that is due to phase modulation of the light. The resulting formula is experimentally verified by a test interferometer with suspended mirrors in the 40-m arms.     

Mirror-orientation noise in a Fabry-Perot interferometer gravitational wave detector

The influence of angular mirror-orientation errors on the length of a Fabry-Perot resonator is analyzed geometrically. Under conditions in which dominant errors are static or vary slowly over time, the analysis permits a simple prediction of the spectrum of short-term cavity length fluctuations resulting from mirror-orientation noise. The resulting model is applicable to the design of mirror control systems for the Laser Interferometer Gravitational-Wave Observatory, which will monitor separations between mirrored surfaces of suspended inertial test bodies as a way to measure astrophysical gravitational radiation. The analysis is verified by measuring the response of the Laser Interferometer Gravitational- Wave Observatory's 40-m interferometer test-bed to the rotation of its mirrors.     

High-bandwidth laser frequency stabilization to a fiber-optic delay line

Stabilization of laser frequency to interferometers with a large time delay in one arm is of significant interest to space-based gravitational wave detectors such as the Laser Interferometer Space Antenna. A recently proposed technique allows a control bandwidth larger than the inverse delay time to be achieved. We present experimental results demonstrating laser frequency stabilization to an optical fiber delay line. A control bandwidth approximately 50 times the inverse delay time is demonstrated.     

Sensing and control in dual-recycling laser interferometer gravitational-wave detectors

We introduce length-sensing and control schemes for the dual-recycled cavity-enhanced Michelson interferometer configuration proposed for the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). We discuss the principles of this scheme and show methods that allow sensing and control signals to be derived. Experimental verification was carried out in three benchtop experiments that are introduced. We present the implications of the results from these experiments for Advanced LIGO and other future interferometric gravitational-wave detectors.     

样条函数在激光跟踪仪测距补偿中的应用

激光跟踪仪测距精度取决于激光干涉仪(IFM)和激光绝对测距仪(ADM)的精度,就目前技术水平而言,IFM测距精度远高于ADM测距精度,因此需要对ADM测距误差进行修正。本文采用三次样条函数对激光跟踪仪全程ADM测距误差进行修正,并与线性误差修正方法进行了对比,结果显示三次样条函数能够更好地拟合误差曲线,改善修正后残余误差的均方差,均方差为0.007 mm,优于最小二乘直线拟合,从而提高激光跟踪仪测距精度和空间测量精度。     

Simple iodine reference at 1064 nm for absolute laser frequency determination in space applications

Using an iodine cell with fixed gas pressure, we built a simple frequency reference at 1064 nm with 10 MHz absolute accuracy and used it to demonstrate deterministic phase locking between two single-frequency lasers. The reference was designed to be as simple as possible, and it does not use a cooler or frequency modulator. This system should be useful, especially for space interferometric missions such as the Laser Interferometer Space Antenna.     

Cavity with a deformable mirror for tailoring the shape of the eigenmode

We demonstrate an optical cavity that supports an eigenmode with a flattop spatial profile--a profile that has been proposed for the cavities in the Advanced Laser Interferometer Gravitational Wave Observatory, the second-generation laser interferometric gravitational wave observatory--because it provides better averaging of the spatially dependent displacement noise on the surface of the mirror than a Gaussian beam. We describe the deformable mirror that we fabricated to tailor the shape of the eigenmode of the cavity and show that this cavity is a factor of 2 more sensitive to misalignments than a comparable cavity with spherical mirrors supporting an eigenmode with a Gaussian profile.     

Dual-recycled cavity-enhanced Michelson interferometer for gravitational-wave detection

The baseline design for an Advanced Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO) is a dual-recycled Michelson interferometer with cavities in each of the Michelson interferometer arms. We describe one possible length-sensing and control scheme for such a dual-recycled, cavity-enhanced Michelson interferometer. We discuss the principles of this scheme and derive the first-order sensing signals. We also present a successful experimental verification of our length-sensing system using a prototype tabletop interferometer. Our results demonstrate the robustness of the scheme against deviations from the idealized design. We also identify potential weaknesses and discuss possible improvements. These results as well as other benchtop experiments that we present form the basis for a sensing and control scheme for Advanced LIGO.     

Fabrication and measurement of optics for the laser interferometer gravitational wave observatory

The manufacture and testing of high-precision optical surfaces for the Laser Interferometer Gravitational Wave Observatory is described. Through the use of carefully shaped polishing laps made of a nondeformable polymer material coated on a rigid base, surfaces 250 mm in diameter with radii of curvature between 7 and 15 km were polished to an accuracy of several hundred meters in the curvature and with low values of waviness and microroughness. Metrology instrumentation used to measure the optical finish included a large-aperture digital interferometer calibrated to nanometer-level accuracy for measurements of curvature, astigmatism, and waviness and an interference microscope for measurements of microroughness. The power spectra of the data from both instruments were in good agreement.     

Modal frequency degeneracy in thermally loaded optical resonators

We observe power coupling from the fundamental mode to frequency-degenerate higher-order spatial modes in optical resonators illuminated with a 30 W laser. Thermally-induced modal frequency degeneracy facilitates power transfer from the fundamental mode to higher-order modes, reduces power coupling into the cavity, and triggers power fluctuations. Modeling thermoelastic deformation of a mirror's surface shows predicted modal frequency degeneracy to be in reasonable agreement with experimental observations. Predictions for the Laser Interferometer Gravitational-wave Observatory (LIGO) show that the circulating fundamental-mode power necessary for gravitational-wave detection is compromised at coating absorptions of 3.8 and 0.44 ppm for Enhanced and Advanced LIGO Fabry-Pérot cavities, respectively.