外差干涉仪中光路调整的分析

分析了共光路外差干涉仪光路中几个组成元件的调整方法 ,包括入射光位置的调整、渥拉斯顿棱镜位置的调整、被测表面位置的调整等。     

"共光路"校准激光干涉仪的测长不确定度

激光干涉仪校准时为了避免引入阿贝误差,通常采用"背对背"测量方法,即标准干涉仪的反射镜与被测干涉仪的反射镜背对背放置,使标准干涉仪与被测干涉仪的光路处于同一直线上.现提出校准激光干涉仪的另一方法,利用同一组分光镜和反射镜,使标准干涉仪与被测干涉仪的光路处于同一光路上,即"共光路"测量方法.这种方法与"背对背"的测量方法相比,具有抗环境干扰的能力强的优点,使由环境条件引入的测量误差最小,其最佳相对测量不确定度优于1×10-7.通过测量数据和标准测量装置的不确定度分析,来评价"共光路"测量方法的优越性.     

用于引力波探测的星间激光干涉测量模拟系统

星间激光干涉仪具有比地面干涉仪更长的干涉臂(10⁶ km),能够探测更低频段0.1 mHz～1 Hz的引力波。星间激光干涉仪具有典型的应答式外差干涉仪结构,其本质是一个光学锁相环。在地面环境下搭建模拟的星间激光干涉仪,成功将从激光器的频率锁定到稳频的主激光器频率上。结果显示：锁相环的锁定时间超过2×10⁴ s,满足了低频信号的探测条件;在较短位移和较长位移的不同条件下,干涉仪无粗大误差。经过分析得出：温度、气压等环境扰动带来的噪声是制约干涉仪精度的关键因素。     

一种新型大尺寸长度校准装置的研制

介绍了一种新型的大尺寸长度校准装置,该装置解决了激光干涉仪等高精度大尺寸长度测量仪器的实验室校准与溯源问题.通过采用三路相干光进行测长,根据两辅助光路与主光路的测长偏差计算阿贝角,实现了阿贝误差的实时补偿.利用标准双频激光干涉仪测试了阿贝误差的补偿精度,35 m测量范围内的比对误差小于±3μm.测量精度达到了单光路同轴测量的水平.     

外差激光干涉仪非线性的细分和消除

通过理论推导得到一个消除外差激光干涉仪非线性的理论,只要改变干涉仪的结构,也就是增加光程倍数,就可以减小激光干涉仪的非线性误差。实验证明,这个方法可以有效地减小双频激光干涉仪的各种非线性误差,不论这个误差是一阶的还是二阶的,也不论是什么原因引起的。它不仅适应于科学实验研究,而且也适应于工业精密测量应用,对纳米测试技术的发展具有实际意义。     

纳米计量与分子坐标测量机系统设计（2）

NanmetrologyandMolecularMeasuringMachineSystemDesign（2）WangJia4分子测量机计量系统STM和AFM均不是计量型仪器，而是作为位置传感器。分子坐标测量机必须采用能够溯源的超高分辨率激光外差干涉仪作为测量参考基准，并测量探针和样品之间的相对运动。激光外差可采用塞曼频率分裂，多模激光器或声光电光调制原理。干涉仪采用了光学8倍频。用相位计从时间间隔分析器中计算相位，其时间分辨率为200pa，电子细分技术实现1000细分。干涉仪的分辨率为0．075um。获得高精度的主要障碍是激光器和干涉仪光学元件中偏振态混合效应和非线性…     

科用外差法测定NH_2D斯塔克盒稳定CO_2激光频率系统的鉴频曲线

本文提出了固定NH_2D分子吸收线型中心频率而改变激光输出频率,用外差拍频计数记录激光频率的变化的外差拍频测定NH_2D Stark盒稳定CO_2激光频率系统中鉴频曲线的方法。利用一支稳频激光器提供参考频率,采用这种方法进行了鉴频曲线的测量。文中给出了实验结果并进行了误差分析。     

外差式激光干涉振动一次校准

文章先扼要介绍ISO 16 0 6 3- 11中所列 3种激光干涉振动一次校准方法 ,以及用零差式迈克耳孙激光干涉仪正弦逼近法实现加速度的灵敏度和灵敏度相移的校准 ,然后在此基础上 ,从原理、结构和使用等方面介绍外差式激光干涉振动一次校准 ,以及PTB如何用外差式激光干涉技术较大幅度地提高与扩展振动校准频率、校准位移等技术。     

基于激光干涉仪数字信号解码的振动校准方法

提出了一种基于Polytec外差激光干涉仪输出S/PDIF数字信号解码的加速度计校准方法,优化了校准过程,并保障了加速度计的灵敏度幅值与相位校准精度.通过与ISO 16063-11推荐的外差激光干涉法在5 Hz～20 kHz频率范围内的校准结果对比,提出方法的灵敏度幅值相对误差与相位差分别小于0.969％和0.165°...     

角振动测量方法的研究

中国计量科学研究院研制出频率范围0.000 5 Hz~1 200 Hz高精度角振动基准装置,低频角振动装置最大角位移300°,中频角振动装置最大角位移60°,角加速度范围为0.04 rad/s~2~2 000 rad/s~2。装置实现了衍射式外差激光干涉仪测量方法,以及圆光栅和双光束外差激光干涉仪差动测量。角加速度复灵敏度测量不确定度(k=2):参考点优于0.5%,0.5°,通频带优于1.0%,1.0°。     

Heterodyne wavelength meter for continuous-wave lasers

A wavelength meter based on a heterodyne interferometer is presented. A single-wavelength test laser beam is modulated to two orthogonal linearly polarized components with different frequencies by a pair of acousto-optic modulators. Then the modulated laser beam and a two-wavelength laser beam are sent to a heterodyne interferometer in a common path. The ratio of two laser interference phase shifts in the heterodyne interferometer is equal to the ratio of their wavelengths. The heterodyne technique measures the heterodyne interference phase but not the interference intensity, which means that it could measure a light source whose intensity is not stable. The heterodyne interference signal is an alternating signal that can easily magnify and process the circuit that makes up the heterodyne wavelength meter and could be used to measure the low-intensity light source even when there are environmental disturbances. A tunable diode laser wavelength range of 630-637 nm has been measured to an accuracy of 5 parts in 10(7).     

Effects of polarization mixing on the dual-wavelength heterodyne interferometer

A great amount of phase fluctuation was observed in the dual-wavelength heterodyne interferometer that we have developed. Through analyses and experiments, we found that this fluctuation was caused by polarization mixing in the interferometer. The errors originating from the polarization mixing were also found to be the first or second harmonic versus the phase change of one mode of the laser in the optical path difference and might become substantial in value. Measures that reduce the polarization mixing and improve the precision of the interferometer are given.     

An analysis of the polarization component of the measurement error in heterodyne laser interferometer measurement systems

The reasons for the occurrence of the polarization component of the measurement error in heterodyne laser interferometer measuring systems are considered. An analysis of this component is given.     

单频激光干涉仪条纹的偏振移相细分技术

提出了一种用于单频激光干涉仪条纹细分的偏振移相技术.通过偏振分光镜、波片等光学元器件产生四路依次相差90°相位的激光干涉信号,经过硬件电路的整形、放大和比较后,可以解决常见的光强"零漂"问题.共光路设计有效地消除了由于环境因素给测量带来的误差,提高了干涉系统的稳定性和重复性.移相技术不仅充分地利用光能量,而且四路信号更便于干涉条纹的计数和判向,同时为电子细分技术奠定了基础.     

第三代激光干涉仪

微片激光自混合干涉仪原理上与迈克尔荪干涉仪不同。主要差别是：激光自混合干涉仪的光束照射在被测物上并被反射回激光器被激光器内放大介质放大。作者课题组研究的的激光自混合干涉仪的测量速度达到了1 m/s以上,10 m空程的环境误差小到了40 nm。它具有全固态,可测“黑”目标的位移等性能,又达到了传统激光干涉仪的技术指标。如果第一代光学干涉仪是以光谱灯做光源,第二代光学干涉仪是以HeNe气体激光器做光源的话,固体激光自混合干涉仪因其激光“自混合”原理可看成是第三代激光干涉仪。     

Heterodyne interferometer with subatomic periodic nonlinearity

A new, to our knowledge, heterodyne interferometer for differential displacement measurements is presented. It is, in principle, free of periodic nonlinearity. A pair of spatially separated light beams with different frequencies is produced by two acousto-optic modulators, avoiding the main source of periodic nonlinearity in traditional heterodyne interferometers that are based on a Zeeman split laser. In addition, laser beams of the same frequency are used in the measurement and the reference arms, giving the interferometer theoretically perfect immunity from common-mode displacement. We experimentally demonstrated a residual level of periodic nonlinearity of less than 20 pm in amplitude. The remaining periodic error is attributed to unbalanced ghost reflections that drift slowly with time.     

Experimental comparison of autodyne and heterodyne laser interferometry using an Nd:YVO₄ microchip laser

Using an Nd:YVO? microchip laser with a relaxation frequency in the megahertz range, we have experimentally compared a heterodyne interferometer based on a Michelson configuration with an autodyne interferometer based on the laser optical feedback imaging (LOFI) method regarding their signal-to-noise ratios. In the heterodyne configuration, the beating between the reference beam and the signal beam is realized outside the laser cavity, while in the autodyne configuration, the wave beating takes place inside the laser cavity, and the relaxation oscillations of the laser intensity then play an important part. For a given laser output power, object under investigation, and detection noise level, we have determined the amplification gain of the LOFI interferometer compared to the heterodyne interferometer. LOFI interferometry is demonstrated to show higher performance than heterodyne interferometry for a wide range of laser powers and detection levels of noise. The experimental results are in good agreement with the theoretical predictions.     

Modeling and Analysis on Alignment Error of Four Path Step Gauge Interferometer

The four path laser interferometer has been used for calibration of step gauge. Preceding studies adopting four path laser interferometer have achieved the expanded uncertainty of about 0.5 μm for 1000 mm. On the other hand, there is a concern remained that the alignment procedure seems to be tedious and the resulted uncertainty estimation becomes an empirical one. The current study aims to build an error model expressing cosine error appeared in the optical system of the four path laser interferometer. The result of model analysis points out that conventional error estimation may cause non-negligible under estimation on cosine error. The model analysis performed to clarify error propagation of angular deflection of plane mirrors of the four path laser interferometer requires thorough consideration for estimating its contribution to the uncertainty.     

偏振混合对双波长外差干涉仪精度的影响分析

本文分析了偏振混合在双波长外差干涉仪中所产生的误差，指出其是干涉仪相位抖动的主要原因．     

大长度激光测量中阿贝误差消除方法的研究

提出一种基于3路独立激光干涉仪消除大长度激光测量中的阿贝误差的方法,3路干涉仪的安装位置可布置成任意三角形。通过3路干涉仪的测量结果及被测仪器与3路干涉仪安装位置的几何关系,构造一路与被测仪器同光路的虚拟干涉仪,推导虚拟干涉仪的测长公式。该算法对干涉仪的安装位置无特殊要求,在实践中易于实现。为验证算法的有效性,依托于室内80 m大长度标准装置,通过改变被测仪器安装位置,在45 m范围内进行了3组不同的验证实验。实验结果显示消除阿贝误差后,残余的其它误差的最大值仅为1.10 μm,该算法可有效地消除阿贝误差。