共查询到20条相似文献,搜索用时 15 毫秒
1.
《Precision Engineering》1999,23(1):39
In this paper, the main causes of scale nonlinearity of a laser interferometer with a single-frequency laser and a quadrature fringe detection system are described. The primary causes of scale nonlinearity are quadrature phase shift error and imperfect optical elements in the interferometer and detection unit. A method for measuring this nonlinearity with an optical compensator is described. Nonlinearities arising from quadrature phase shift error, unequal amplitudes, and electronic offsets in the detection unit can be compensated by means of a PC program as described herein. By using a differential interferometer with a resolution of 0.3 nm, the nonlinearity compensation was experimentally verified, and by averaging the measured values for 20 s, a linearity better than ±0.5 nm was achieved. 相似文献
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This paper describes a 561 nm laser heterodyne interferometer that provides time-resolved measurements of line-integrated plasma electron density within the range of 10(15)-10(18) cm(-2). Such plasmas are produced by railguns on the plasma liner experiment, which aims to produce μs-, cm-, and Mbar-scale plasmas through the merging of 30 plasma jets in a spherically convergent geometry. A long coherence length, 320 mW laser allows for a strong, sub-fringe phase-shift signal without the need for closely matched probe and reference path lengths. Thus, only one reference path is required for all eight probe paths, and an individual probe chord can be altered without altering the reference or other probe path lengths. Fiber-optic decoupling of the probe chord optics on the vacuum chamber from the rest of the system allows the probe paths to be easily altered to focus on different spatial regions of the plasma. We demonstrate that sub-fringe resolution capability allows the interferometer to operate down to line-integrated densities of the order of 5 × 10(15) cm(-2). 相似文献
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V. S. Terent’ev 《Optoelectronics, Instrumentation and Data Processing》2012,48(4):358-368
Numerical simulation was used to demonstrate the possibility of designing a two-mirror multibeam reflective diffraction interferometer using a single-mode fiber with a cladding. The method is based on the calculation of the multimode and multibeam interference of the cladding modes in the fiber describing the diffraction on a diffuser made in the form of an insert of a different fiber as part of one of the interferometer mirrors. It is shown based on bulk optics that using certain optimization, one can obtain a reflection-response function profile of this interferometer similar to that of the transmission-response function of a Fabry-Perot interferometer. 相似文献
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B.A.W.H. Knarren S.J.A.G. Cosijns H. Haitjema P.H.J. Schellekens 《Precision Engineering》2005,29(2):1373
In this paper the validation of a fiber-fed heterodyne laser interferometer with nanometre uncertainty is presented. The achievable displacement measurement uncertainty is investigated for different polarisation maintaining fibres used in these interferometers. Measurement results are shown for both a range of m as well as a range of 300 mm. It is shown that a (selected) PM-fibre with an extinction ratio of 1:1650 and the use of an external reference allows realising a fibre-fed laser interferometer able to measure displacements with the same uncertainty as a laser interferometer system without fibre. Tests were performed with fibres ranging in length up to 50 m. 相似文献
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Sanjuán J Preston A Korytov D Spector A Freise A Dixon G Livas J Mueller G 《The Review of scientific instruments》2011,82(12):124501
The laser interferometer space antenna (LISA) is a mission designed to detect low frequency gravitational waves. In order for LISA to succeed in its goal of direct measurement of gravitational waves, many subsystems must work together to measure the distance between proof masses on adjacent spacecraft. One such subsystem, the telescope, plays a critical role as it is the laser transmission and reception link between spacecraft. Not only must the material that makes up the telescope support structure be strong, stiff, and light, but it must have a dimensional stability of better than 1 pm Hz(-1/2) at 3 mHz and the distance between the primary and the secondary mirrors must change by less than 2.5 μm over the mission lifetime. Carbon fiber reinforced polymer is the current baseline material; however, it has not been tested to the pico meter level as required by the LISA mission. In this paper, we present dimensional stability results, outgassing effects occurring in the cavity and discuss its feasibility for use as the telescope spacer for the LISA spacecraft. 相似文献
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A dispersion interferometer is one of the promising methods of the electron density measurement on large and high density fusion devices. This paper describes development of a CO(2) laser dispersion interferometer with a photoelastic modulator for phase modulation. In order to make the dispersion interferometer free from variations of the detected intensity, a new phase extraction method is introduced: The phase shift is evaluated from a ratio of amplitudes of the fundamental and the second harmonics of the phase modulation frequency in the detected interference signal. The proof-of-principle experiments demonstrate the feasibility of this method. 相似文献
8.
Dr-Ing H.-H. Schüssler 《Measurement》1985,3(4):175-184
The paper describes the reasons and practical needs for the calibration of laser interferometer systems. The conventional techniques for mechanical, frequency and wavelenght comparison, and the new co-axial displacement comparator for simultaneous concurrent comparison of up to 10 complete laser interferometer systems, are explained. Requirements of the set-up and experimental results are discussed. The new method gives the ordinary user a simple but efficacious measure to calibrate his own complete laser interferometer system and to estimate the effective precision under his own real laboratory or workshop conditions. Even the comparison of uncalibrated systems gives interesting results: eg, about zero drift, warming up, short- and long-term alterations and electrical noise interferences. For absolute calibration, a portable iodine-stabilised laser source and sophisticated methods for wavelenght compensation in ambient air are needed. 相似文献
9.
为了定标测量系统、提高测量精度,在简要论述了激光球面干涉仪的原理以后,采用移相技术,获得了四幅干涉图,并提取出范围在[-π,π)之间的相位。然后,利用相位消跳变算法,展开得到连续的相位。最后经过消倾斜和离焦等后继处理,得到了系统的波面误差。 相似文献
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The linewidth of a distributed-feedback (DFB) diode laser at 1156 nm, of which free-running linewidth was 3 MHz, was reduced to 15 kHz using an all-fiber interferometer with 5-m-long path imbalance. Optical power loss and bandwidth limitation were negligible with this short optical fiber patch cord. This result was achieved without acoustic and vibration isolations, and the frequency lock could be maintained over weeks. In addition to its simplicity, compactness, robustness, and cost-effectiveness, this technique can be applied at any wavelength owing to the availability of DFB diode lasers and fiber-optic components. 相似文献
12.
A single-axis measuring microscope has been constructed for the calibration of stage micrometers, micrometer microscopes and similar devices which require uncertainties down to 0.1 μm. The instrument is built from modules so that the interferometer measuring unit can be used in a variety of calibration tasks. A single mode optical fibre can be used to couple the laser source to the interferometer 相似文献
13.
A new species of laser Doppler velocimeter is presented based on wavelength detection with a two-beam interferometer. A finite optical path difference, Deltaphi, of the interferometer creates a sensitivity of the interference to wavelength changes. By means of a fast feedback system, the phase, Deltaphi/lambda is kept constant. Wavelength changes are immediately answered by changes of Deltaphi generated with a Pockels cell. The Pockels cell voltage represents a continuous signal proportional to the instantaneous velocity component of the scattering object. A time resolution of 1 micros or lower can be obtained. The field of applications includes velocity recordings in gas flows containing tracer particles as well as velocity recordings of moving surfaces. A number of experiments are described demonstrating the performance of the system. 相似文献
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Highly precise and stable displacement-measuring laser interferometer with differential optical paths 总被引:1,自引:0,他引:1
Shigeru Hosoe 《Precision Engineering》1995,17(4):258-265
To achieve sub-nm precision of a displacement-measuring laser interferometer, its optical systematic error should be made as small as possible. In this paper, methods to reduce the optical path length changes and stray light reflections, as well as materials appropriate for main optical elements in the optical layout and the holders, are discussed. As a solution, a complete differential interferometer using a quartz plate inclined 45° to the optic axis is presented. This interferometer has null dead path length, fewer and smaller optical elements, and fewer boundary surfaces with air than conventional differential interferometers. Adopting the athermal glass (Ultran30) for interferometric prisms and aluminum alloy (A5056) for the interferometric prism holder was effective in reducing the drift of measurement caused by thermal changes. The interferometer made of Ultran30 glass with a A5056 holder achieved 0.31 nm/K thermal drift in the displacement measurement. 相似文献
17.
The nonlinear errors of high-precision linear encoders were calibrated by using a nanometer-length calibrator that was based on the optical-zooming laser interferometer with an optical frequency comb. A transmission-type linear encoder and a reflection-type linear encoder were calibrated, and the cyclic nonlinear errors were evident. The magnitudes of the observed cyclic errors were 0.1 nm and 0.2 nm, respectively, and the best calibration uncertainties were 0.55 nm (k = 2). A traceable calibration service for linear encoders with the best calibration uncertainty in the sub-nanometer range has started based on this work. 相似文献
18.
A. G. Kuznetsov 《Optoelectronics, Instrumentation and Data Processing》2013,49(4):383-398
This paper reviews studies of the possibility of controlling the output spectrum of Qswitched fiber lasers. Various laser configurations for producing output radiation with characteristics optimized for specific applications, such as high-power pulses for micromachining of materials, probe pulses in fiber-optic sensor systems, etc., are considered. The mechanism of broadening of the lasing line is elucidated, and methods for controlling the output spectrum in Q-switched all-fiber lasers are described. Frequency tuning in the amplification line and generation of higher harmonics in nonlinear crystals are considered. 相似文献
19.
Lesage A Richou J Charil P Combier M Lebrun JL 《The Review of scientific instruments》1979,50(10):1306
An improved method for high-electron-density (10(17) cm(-3)) measurement in a shock-generated plasma is described. A laser interferometer operated at 3.39 mum is regularly modulated (1 MHz) by a LiNbO(3) electro-optical crystal. Thus electron-density variations of 8x10(15) cm(-3) mus(-1) and fluctuation of 8x10(14) cm(-3) can be simultaneously and accurately measured in a 4x4-cm conventional shock tube. Experimental results in reflected shock waves are presented. 相似文献
20.
设计并搭建了重复频率长时精确锁定的783 nm飞秒光纤激光器。该激光器基于全保偏非线性干涉环镜(NALM),实现掺铒光纤振荡器锁模脉冲输出,由与脉冲分离器级联的环境稳定掺铒光纤双级放大器进行功率放大,实现了平均功率1.30 W、脉冲宽度130 fs、重复频率77.1 MHz、1 560 nm脉冲输出;通过周期极化铌酸锂(PPLN)光学晶体倍频,获得了平均功率为0.52 W、脉冲宽度为140 fs、783 nm脉冲输出。通过重复频率监测及锁相环技术,进一步将掺铒光纤振荡器的重复频率溯源至参考铷原子钟,12 h内频率抖动峰-峰值为5 mHz、标准偏差为1.2 mHz。该激光器系统具有稳定性高、集成度高、体积小的特点。 相似文献