共查询到20条相似文献,搜索用时 46 毫秒
1.
The solution of the phase problem in optics as applied to the analysis of time-dependent signals and the character of action of a medium under study on the probing radiation is considered using a two-beam interferometer with phase modulation in one of the channels and a spectral device. The analysis relates, in particular, to ultrashort signals and processes. To ensure a frequency shift in the interferometer channel, an electro-optic crystal of the type of ferroelectric perovskites was used as a modulator. The analysis of errors for the amplitude and phase structures determined is performed. 相似文献
2.
Parameters of a spectrochronograph that represents a Fabry-Perot interferometer combined with a spatial-time analyzer (a streak camera) are analyzed. Using numerical simulation, time scans of interferograms for bandwidth-limited and phase-modulated pulsed optical signals are obtained. The conditions are determined under which a Fabry-Perot interferometer represents a high-accuracy instrument for measuring the timeresolved spectral dynamics of short optical signals. In particular, an adequate representation of relatively smooth and monotone changes in amplitude and phase characteristics of an optical signal in a spectrochronograph requires that the mode lifetime in a Fabry-Perot interferometer be matched to the time scale of changes in the spectral structure of a pulse being studied. The character of distortions formed in the time-resolved spectral patterns in the case where these conditions are not fulfilled is qualitatively determined, and quantitative estimates of the distortions are presented. The results of the analysis and the numerical calculations show that a spectrochronogram obtained using a Fabry-Perot interferometer and a time analyzer (a streak camera) with parameters corresponding to the criteria formulated in the paper enable one to obtain information on the initial amplitude-phase pattern of a light pulse. 相似文献
3.
分布反馈光纤激光器水听器设计与实验 总被引:2,自引:2,他引:0
为验证分布反馈光纤激光器水听器具有抗干扰强、动态范围大、灵敏度高等独特优点,进行了该水听器的系统设计,并给出分布反馈光纤激光器的输出特性曲线.采用非平衡M-Z光纤干涉仪进行分布反馈光纤激光器水听器的解调,结合工作点扫描和控制的测量方法,利用压电陶瓷相位调制器来进行相位补偿,使系统稳定工作在最灵敏处.采用制作的光纤干涉仪,搭建室内水听器模拟对比实验,通过扬声器产生1.34 KHz和7.24 KHz的高频周期激励信号,以及对水听器进行敲击激励,分析水听器的响应.进行了激光器水听器和压电水听器低频频响特性对比测试,实验得出光纤激光器水听器的光电探测输出信号的信噪比高,可以准确、可靠地反映原始声信号. 相似文献
4.
Zhijun Li 《Optics Communications》2008,281(18):4744-4746
Based on Michelson interferometer and phase generated carrier (PGC) homodyne demodulation technique, an optical interferometer system is built, and a novel method using the central angles of Lissajous figures to measure micro-vibration displacement is proposed. The Lissajous figures are obtained by synthesizing two interferometric signals that their vibration directions are orthogonal and their intensities are equal. Through theoretical analysis, software simulation and experimental test, it is concluded that the central angles of Lissajous figures have a linear relationship with the phase modulation coefficients and the micro-vibration displacements when the phase modulation coefficients are small. So the micro-vibration displacements can be directly obtained by measuring the central angles of Lissajous figures. The method is simple and convenient. The experimental results indicate that the micro-vibration displacements measuring range can reach 5-775 nm, with a resolution of about 5 nm. 相似文献
5.
Chen Jun-Ben Gao Xiang 《International Journal of Infrared and Millimeter Waves》1989,10(10):1207-1211
Usually, both the probing and reference signals received by LATGS detectors of FIR interferometer pass through hardware phase discriminator and the output phase difference--hence the electron line densities is collected for analysis and display with a computerized data acquisition system(DAS). In this paper, a new numerical method for computing the phase difference in software has been developed instead of hardware phase discriminator, the temporal resolution and stability is improved. An asymmetrical Abel inversion is applied to processing the data from a seven-channel FIR HCN laser interferometer and the space-time distributions of plasma electron density in the HT-6M tokamak are derived. 相似文献
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7.
We introduce a heterodyne interferometer scheme utilizing the double-pass arrangement of the deflected beams of an acousto-optic modulator. To prove our new idea, the interferometer has been applied for measuring small amplitude vibrations. The output intermediate frequency signal from the interferometer is processed by using an I/Q demodulator. In theory, it can provide the quantum noise limited sensitivity, whereas, in our present Letter, the sensitivity of the phase measurement is limited by the resolution of the 16?bit A/D converter used for processing the I/Q signals. Details of our interferometer scheme are discussed. 相似文献
8.
P. N. V’yugin V. G. Gavrilenko L. M. Kustov A. I. Mart’yanov M. B. Nechaeva 《Radiophysics and Quantum Electronics》2007,50(2):87-94
We consider the interferometer method by which a turbulent water flow is remotely studied by sounding with a noise ultrasound
signal. It is shown that the processing of signals received by two spatially separated receivers makes it possible to extract
the signal phase difference caused by the concentration fluctuations of cavity air bubbles on the propagation paths. Spectral
analysis of the random phase difference permitted diagnostics of the propagation medium. In particular, it is shown that the
output signal of the interferometer carries information on the spatial spectrum of parameter fluctuations of the medium, and
on the velocity of inhomogeneities if the interferometer base is parallel to the turbulent flow.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 50, No. 2, pp. 95–103, February 2007. 相似文献
9.
We present a new method for the measurement of the phase of ultrashort optical pulses with high spectral resolution. This
employs an interferometer with a monochromator in one arm. Two detectors operating in single photon and two-photon absorption
regimes monitor the output from the interferometer. Comparison of the signals from the two detectors gives a measurement of
the phase of the light pulse. The principles underpinning this technique are discussed and the experimental application to
picosecond pulses is demonstrated. 相似文献
10.
Non-contact detection of laser-generated surface acoustic waves using fiber optic Sagnac interferometer 总被引:1,自引:0,他引:1
A high powered Q-switched Nd:YAG laser was used to excite the surface waves, and an optical fiber sensor was used to detect the out-of-plane displacements due to the propagating waves. This sensor is based on the fiber optic Sagnac interferometer, which has the path-matched configuration and does not require active stabilization. Quadrature phase bias between two interfering laser beams in the Sagnac loop is applied by controlling the birefringence in an optical path using a fiber polarization controller. A stable quadrature phase bias can be confirmed by observing the interferometer output according to the change of phase bias. Additional signal processing is not needed for the detection of ultrasonic waves using the Sagnac interferometer. The performance of the fiber optic Sagnac interferometer was investigated, and laser-generated surface wave signals were detected using this fiber optic sensor. The developed fiber optic sensor configured in this study is very simple and is effective for non-contact detection of ultrasonic waves. 相似文献
11.
12.
We propose and experimentally demonstrate the generation of a pair of polarity-reversed 24 GHz millimeter-wave (MMW) ultra-wideband (UWB) monocycles. The scheme is realized by using delay interferometer (DI) based phase modulation to intensity modulation (PM–IM) conversion and carrier suppression modulation (CSM) based frequency up-conversion. The phase modulation is realized by using either electro-optic phase modulator (EOPM) or cross phase modulation (XPM) in semiconductor optical amplifier (SOA), which is an all-optical approach to obtaining baseband UWB signals, respectively. After frequency up-converted by using CSM in a Mach–Zehnder modulator (MZM), a pair of polarity-reversed 24 GHz MMW-UWB signals complying with the Federal Communication Committee (FCC) requirements is generated. The bi-phase modulation (BPM) of 24 GHz MMW-UWB signals can also be realized by electrically switching the bias voltage of delay interferometer. 相似文献
13.
We present two displacement sensing techniques which rely on amplitude variations of Bessel frequency components contained in the photodetected output of a phase modulated two-beam interferometer. Experimental results demonstrate demodulated output signals that correspond to the absolute optical path difference between the two arms of an interferometer. Optical displacements over a 50 mm range have been recorded with a resolution of 25 microns. Both approaches are suitable for passive remote sensing applications. 相似文献
14.
为了实现更高分辨率的激光频率扫描干涉测量, 增大光源的扫频范围以及减小扫描频率的非线性成为关键. 采用外腔式大带宽扫频光源结合光纤辅助干涉仪构建的外部时钟频率采样非线性校正是目前较为常用的方法. 本研究发现随着扫频带宽和测量范围的增加, 光纤辅助干涉仪与测量光路中存在的色散失配导致频谱出现严重展宽, 极大的降低了测量的分辨率. 本文建立了辅助干涉仪和测量干涉仪色散失配影响的理论模型, 利用该模型分析了扫频带宽和测量范围与测量分辨率的变化关系, 与实验结果相一致, 并进而提出了基于峰值演化消畸变的色散相位补偿方法, 有效地提高了测量的分辨率, 在2.53 m 处实现了接近理论值的64.5 μm的测量分辨率. 该色散失配模型及补偿方法为提高大尺寸激光频率扫描干涉仪的测量分辨率及测距范围提供了参考. 相似文献
15.
N. Bennis I. Merta A. Kalbarczyk M. Maciejewski P. Marc A. Spadlo L.R. Jaroszewicz 《Opto-Electronics Review》2017,25(2):69-73
We propose real time phase measurements in liquid crystals cells using Young's interferometer constructed with a new principle with possibility to control the distance between two point sources. The optical interference optical pattern is detected by a bicell photo-detector in a back Fourier focal plane. A phase modulation controlled by a monopixel liquid crystals’ cell placed in a reference arm of interferometer is observed as a dynamic shift of the fringes’ pattern in spatial domain. Concept of signals’ demodulation in the Fourier focal plane will be described using a new approach to the demodulation signals. In this work we evaluate the demodulation condition of our setup and we present measurements of a dynamic phase response for nematic liquid crystals and antiferroelectric liquid crystals cells. 相似文献
16.
V. A. Zubov T. T. Sultanov A. F. Tavasiev A. N. Torgashin 《Journal of Russian Laser Research》1992,13(2):140-151
Results are presented of model-based experimental investigations of an interference correlator intended for the measurement of small phase shifts of radar signals received from two antennas. The correlator is based on a Mach-Zender interferometer system. Introduction of a radio signal for the data reduction was simulated by phase diffraction gratings placed in the interferometer arms and displaced relative to one another. The operation of the system was investigated in a regime with measurements in the region of the extrema of the correlation function and in a regime with measurements near zeros (extrema of the derivative) of the correlation function. The investigations were carried out for signals formed in first, second, and third order of diffraction. It is shown that the sensitivity of the system for measurements in the region of a correlation-function zero is higher by an order of magnitude than in the extrem~ m region. It is shown that for radio signals in the 100-MHz band, with allowance for the experimental measurement error, the accuracy of determining the time delays reaches 10–11 sec. The accuracy with which geometric displacements of diffraction gratings are determined reaches 5·10-5 mm.Lebedev Physics Institute. Severo-Osetinsk State University. 相似文献
17.
WANG Tingyun * SUN Shenghe 《Chinese Journal of Lasers》1998,7(5):407-412
1IntroductionFiberopticringresonators(FORR)havebeeninvestigatedforanumberofyearsforfiberopticdelayelements[1],sensorapplica... 相似文献
18.
I. M. Belousova N. G. Mironova A. G. Skobelev M. S. Yur’ev 《Optics and Spectroscopy》2007,102(5):760-764
The possibility of creating femtosecond optical switches based on fullerene-containing media is studied numerically. Two approaches to the problem are considered, namely, a film of a fullerene-polymer solid solution and a fullerene film obtained by vacuum deposition. In both cases, the films are placed into a Fabry-Perot interferometer. The polarization nonlinearity of fullerene allows a light-induced change in the refractive index. The possibility of controlling the interferometer transmission using low-intensity signals is demonstrated. 相似文献
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20.
This paper introduces a dual-path heterodyne Mach-Zehnder interferometer adopted for wavelength shift determinations. In this interferometer, two parallel incident beams are separated into two interference pairs which are then recombined to generate two interference signals. A parallel plate is placed on the path of one wave of an interference pair, so the phase difference of the interference signals is a function of the plate and beam wavelength, and the interferometer is thus able to determine the wavelength shift of the incident beam. A setup constructed to realize the proposed interferometer is described, it shows that the interferometer has a resolution up to 1.1 × 10−10 (λ2/nm), and the experimental results of applying this setup not only agree the validity of the interferometer but also indicate that the interferometer has a stability of 6.5 × 10−10 (λ2/nm). 相似文献