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Showing papers on "Interferometry published in 1986"


Book
01 Jan 1986
TL;DR: In this paper, a theory of interferometry and synthesis imaging analysis of the Interferometer Response Geometric Relationships and Polarimetry Antennas and Arrays Response of the receiving system Design of the Analog Receiving System Digital Signal Processing Very-Long-Baseline Interferometry Calibration and Fourier Transformation of Visibility Data Deconvolution, Adaptive Calibrration, and Applications Interferometers Techniques for Astrometry and Geodesy Propagation Effects Van Cittert-Zernike Theorem, Spatial Coherence, and
Abstract: Preface to the Second Edition Preface to the First Edition Introduction and Historical Review Introductory Theory of Interferometry and Synthesis Imaging Analysis of the Interferometer Response Geometric Relationships and Polarimetry Antennas and Arrays Response of the Receiving System Design of the Analog Receiving System Digital Signal Processing Very-Long-Baseline Interferometry Calibration and Fourier Transformation of Visibility Data Deconvolution, Adaptive Calibration, and Applications Interferometer Techniques for Astrometry and Geodesy Propagation Effects Van Cittert-Zernike Theorem, Spatial Coherence, and Scattering Radio Interference Related Techniques Principal Symbols Author Index Subject Index

2,025 citations


Journal ArticleDOI
TL;DR: In this paper, a Lie-group-theoretical approach to the analysis of interferometers is presented, which can achieve phase sensitivity Δo approaching 1/N, where N is the total number of quanta entering the interferometer, provided that the light entering the input ports is prepared in a suitable quantum state.
Abstract: A Lie-group-theoretical approach to the analysis of interferometers is presented. Conventional interferometers such as the Mach-Zehnder and Fabry-Perot can be characterized by SU(2). We introduce a class of interferometers characterized by SU(1,1). These interferometers employ active elements such as four-wave mixers or degenerate-parametric amplifiers in their construction. Both the SU(2) and SU(1,1) interferometers can in principle achieve a phase sensitivity Δo approaching 1/N, where N is the total number of quanta entering the interferometer, provided that the light entering the input ports is prepared in a suitable quantum state. SU(1,1) interferometers can achieve this sensitivity with fewer optical elements.

951 citations


Journal ArticleDOI
TL;DR: In this paper, a method for accurate phase determination in holographic interferometry using a one- or two-dimensional Fourier transform is described, which calculates the interference phase pointwise, even between fringe extrema, and thus has advantages over conventional fringe-finding and tracking methods.
Abstract: A method for accurate phase determination in holographic interferometry using a one- or two-dimensional Fourier transform is described. The method calculates the interference phase pointwise, even between fringe extrema, and thus has advantages over conventional fringe-finding and -tracking methods. Only one interference pattern may be used, although the use of two patterns reconstructed with a mutual phase shift permits an easier phase unwrapping and determination of nonmonotonic fringe-order variations. Additionally, the method offers a means for filtering out disturbances such as speckle noise and background variations.

433 citations


Journal ArticleDOI
TL;DR: In this paper, the authors focus on the amount and nature of information about the image present in the measurements, which has become increasingly relevant with the growth of interferometry, where the data correspond to the Fourier transform of the image.
Abstract: Imaging the two-dimensional intensity distribution of the sky has always been an important part of astronomy. This is particularly true at present, a time when aperture synthesis mapping is firmly established in radio astronomy, charge-coupled devices are revolutionizing optical imaging, and X-ray-imaging cameras are being flown in space. Atmospheric irregularities, instrument aberrations, detector noise, and the diffraction limit all cause the observed image to deviate from the ideal one. Image restoration techniques have therefore had a long history. The field owes much to the classic papers of Bracewell & Roberts ( 12) and Fellgett & Linfoot (35), which focused attention on the amount and nature of information about the image present in the measurements. These ideas have become increasingly relevant with the growth of interferometry, where the data correspond to the Fourier transform of the image. The Michelson stellar interferometer (82) was an early application in optical astronomy. However, it is at radio frequencies where interferometry has proved most fruitful and where astronomers have had to face the problem

405 citations


Journal ArticleDOI
TL;DR: In this article, the behavior of the power spectrum of an external cavity semiconductor laser has been studied using a delayed self-heterodyne interferometric technique that uses delay times less than the laser's coherence time.
Abstract: The behavior of the power spectrum of an external cavity semiconductor laser has been studied using a delayed self-heterodyne interferometric technique that uses delay times less than the laser's coherence time. Experimental results show that the resulting power spectrum is consistent with the theoretical model. However, there is evidence that additional frequency fluctuations are present that cause the delta function portion of the power spectrum to have a finite width.

346 citations


Patent
25 Nov 1986
TL;DR: In this paper, a variable interferometric device consisting of a Fabry-Perot interferometer composed of a pair of reflecting substances facing each other with a space therebetween formed by spacers and a means for deforming at least one of the reflecting substances constituting said FabryPerot Interferometer to thereby change the inter-ferometric characteristics of said Faby-Perone interferometers is presented.
Abstract: A variable interferometric device comprising a Fabry-Perot interferometer composed of a pair of reflecting substances facing each other with a space therebetween formed by spacers and a means for deforming at least one of the reflecting substances constituting said Fabry-Perot interferometer to thereby change the interferometric characteristics of said Fabry-Perot interferometer. Moreover, an optical sensor comprising a light source, a first Fabry-Perot interferometric device, the interferometric characteristics of which vary with the physical quantity of the object to be measured, a light-dividing means for dividing the light from the light source into a first light beam and a second light beam, a second Fabry-Perot interferometric device functioning as a reference standard, the operational conditions of which are set at fixed values, a first photodetector for receiving the first light beam from said light-dividing means through the second Fabry-Perot interferometric device, a second photodetector for receiving the second light beam from said light-dividing means through the second Fabry-Perot interferometric device, and a signal-processing circuit for comparing the output signal from the first photodetector with the output signal from the second photodetector to thereby determine the physical quantity of the object to be measured.

312 citations


PatentDOI
TL;DR: Sub-Nyquist interferometry (SNI), an extension of PSI, is described and demonstrated to overcome the inability to measure surfaces with large aspheric departures, and it preserves the measurement precision that is inherent to PSI.
Abstract: A technique is described for extending the measurement range of interferometry past the Nyquist limit of the sampling frequency of the interferogram. The absolute phase values measured by an interferometer are reconstructed by applying constraints based upon a priori knowledge of the absolute phase values. The constraints include the knowledge that one or more derivatives of the spatial distribution of phase values is a continuous function, and the knowledge of step heights to within λ/2.

214 citations


Journal ArticleDOI
TL;DR: Interferometre a modulation de phase sinusoidale dans lequel une onde de reference est facilement modulee en phase avec un miroir vibrant.
Abstract: Interferometre a modulation de phase sinusoidale dans lequel une onde de reference est facilement modulee en phase avec un miroir vibrant

213 citations


Journal ArticleDOI
TL;DR: This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using a laser diode, which is a kind of multiwavelength interferometry using a single light source.
Abstract: This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using a laser diode. This method uses the fact that the wavelength of the emitted light of a laser diode varies in proportion to the diode’s injection current. The phase difference between the two interfering beams varies due to the sinusoidal variation of wavelength. The variation of the phase difference is detected by the optical heterodyne method. The magnitude of the variation is proportional to the measuring distance and the light wavelength shift. If the wavelength shift is known, a distance larger than the wavelength can be obtained from measurement of the phase variation. This method is a kind of multiwavelength interferometry using a single light source. We have done some fundamental experiments with this method and have confirmed its applicability to practical applications.

207 citations


Journal Article
TL;DR: Fournier theory deconvolution phase recovery reconstruction from projections Specke imaging and interferometry image processing system design program categories technical practicalities as mentioned in this paper, and Fournier Theory of Deconvolution Phase Recovery from projections
Abstract: Setting the scene Fournier theory deconvolution phase recovery reconstruction from projections Specke imaging and interferometry image processing system design program categories technical practicalities

198 citations


Proceedings ArticleDOI
15 Sep 1986
TL;DR: A first series of clinical measurements of patients with angiological problems has shown a clear correlation of the interferometrically measured fundus pulsations with circulation conditions, indicating a very high potential precision of this new technique.
Abstract: If the pupil of the eye is illuminated by a collimated laser beam the light returning from the eye exhibits Newton's interference fringes. This phenomenon can be used (1) to measure fundus tissue pulsations and (2) to measure the optical length of the eye. A first series of clinical measurements of patients with angiological problems has shown a clear correlation of the interferometrically measured fundus pulsations with circulation conditions. First measurements of the optical length of human eyes indicate a very high potential precision of this new technique.

Journal ArticleDOI
TL;DR: The concept of a 3 d laser tracking interferometer system is described in this paper and preliminary results obtained from a two-dimensional version of the system are presented.
Abstract: There is a growing worldwide effort to develop internationally accepted procedures and terminology for the measurement and description of robot performance. One of the most difficult problemss is that of determining the positional accuracy of an industrial robot throughout its large work zone. The concept of a 3 d laser tracking interferometer system is described in this paper and preliminary results obtained from a two-dimensional version of the system are presented. The full 3 d system is currently being constructed.

Journal ArticleDOI
TL;DR: In this paper, a new technique called picosecond interferometry is proposed for the study of phonons in the Brillouin frequency range in transparent materials, which makes possible the measurement of longitudinal phonon velocity and attenuation under conditions such that the conventional approach is not applicable.

Journal ArticleDOI
TL;DR: In this article, closed-form theoretical expressions for the autocovariance function, variance, and noise power spectral density of the instantaneous output intensity are presented for any optical biasing phase and any source coherence time.
Abstract: Dynamic range of many optical signal processing and sensing devices incorporating two-beam interferometers (such as Mach-Zehnder and Michelson interferometers) can be limited by random phase fluctuations of the optical source emission field. This paper is concerned with the intensity fluctuations, originating from the laser source phase noise, at the output of a two-beam interferometer. Closed-form theoretical expressions are presented for the autocovariance function, variance, and noise power spectral density of the instantaneous output intensity which are valid for any optical biasing phase and any source coherence time. Application of the results in the noise performance evaluation of optical devices incorporating two-beam interferometers will also be shown.


Journal ArticleDOI
TL;DR: In this paper, a variation of electronic speckle pattern interferometry (ESPI) is presented whereby phase fringes are produced in contrast to speckles correlation fringes.

Book ChapterDOI
01 Jan 1986
TL;DR: In this article, a detailed summary of recent optical studies of lithium fluoride (LiF) is provided, and a modified form of the Gladstone-Dale relation is presented which correctly models the latest LiF measurements.
Abstract: Laser interferometer systems provide a means for probing the refractive index of transparent specimens subjected to dynamic compression. Previous interferometer measurements of optical properties under shock loading are reviewed for polymethyl methacrylate, fused silica, sapphire, nitromethane, and an aqueous solution of zinc chloride; various degrees of departure from Gladstone-Dale behavior are noted for these materials. In addition, a detailed summary of recent optical studies of lithium fluoride (LiF) is provided. Interferometer data from plate-impact experiments verify sustained LiF transparency for Hugoniot stresses to at least 160 GPa, and establish the variation of LiF refractive index for shock amplitudes ranging from 1.58 to 115 GPa. The refractive-index data for LiF agree with earlier static and shock-wave data, and exhibit a pronounced deviation from predictions based on the Gladstone-Dale, Lorentz-Lorenz, and Drude relations. A modified form of the Gladstone-Dale relation is presented which correctly models the latest LiF measurements. Potential applications of LiF and other window materials to dynamic high-pressure experimentation are discussed.

Journal ArticleDOI
TL;DR: The interaction of surface acoustic Rayleigh pulses with surface-breaking defects has been experimentally studied and it is shown that reflected waveforms from a defect possess two major components.
Abstract: Abstruct-The interaction of surface acoustic Rayleigh pulses with surface-breaking defects has been experimentally studied. The pulses were generated using a Q-switched Nd:YAG laser, and were detected by either a ball capacitance transducer or a laser interferometer. It is shown that reflected waveforms from a defect possess two major components. The first arises from direct reflection of a Rayleigh pulse from the top of the defect, while the second appears to arise from a shear pulse originating from the base of the defect, which is then mode-converted to a Rayleigh pulse on reaching the metal's surface. This model is supported by further experiments which examined interaction with 90" and 270" corners, as well as down-steps. The results offer a new laser technique for measuring defect depths in the range 0.1 to 5 mm.

Patent
03 Oct 1986
TL;DR: In this article, a fiber optical fiber fluid flow measuring device is provided for in vivo determination of blood flow in arteries, which includes an optical fiber sensor which is positioned in the blood flow passage in a restricted flow area.
Abstract: A fiber optical fiber fluid flow measuring device is provided for in vivo determination of blood flow in arteries. The device includes a fiber optical fluid differential pressure measuring device having at least one optical fiber sensor which optical fiber sensor is positioned in the blood flow passage in a restricted flow area. The fiber optical differential pressure fluid sensor is connected to a divided interferometer associated with an opto-electronic demodulator which has an output signal representing the differential pressure in the sensed area. The device also has utility in industrial applications.

Patent
04 Mar 1986
TL;DR: In this paper, a sheet charge density sensitivity of 2.6×108 e/cm2 / √Hz was extracted from experimental data for 1 mA of detected photocurrent.
Abstract: Disclosed is a technique for probing dynamic sheet charge density variations in integrated semiconductor devices. Using a specially designed non-invasive Nomarski phase contrast interferometer a sheet charge density sensitivity of 2.6×108 e/cm2 / √Hz is extracted from experimental data for 1 mA of detected photocurrent. The charge density sensitivity makes possible μV signal level detection in an active device, and with digital signals the corresponding signal/noise level is sufficiently high that multi-mega-baud data can be captured in real time.

Journal ArticleDOI
TL;DR: A phase-conjugate Michelson interferometer using an internally self-pumped barium titanate crystal as reflectors has been constructed to perform parallel image subtraction, intensity inversion, and exclusive or logic operation.
Abstract: A phase-conjugate Michelson interferometer using an internally self-pumped barium titanate crystal as reflectors has been constructed to perform parallel image subtraction, intensity inversion, and exclusive or logic operation. These operations are independent of the optical path differences and phase aberration.

Patent
19 Mar 1986
TL;DR: In this paper, an improved two-wavelength phase-shifting interferometry was proposed to construct steep surface profiles, such as for aspheric surfaces, using improved 2W phase shifting interferometers.
Abstract: An improved apparatus and method are described for accurately "reconstructing" steep surface profiles, such as for aspheric surfaces, using improved two-wavelength phase-shifting interferometry, wherein single-wavelength precision is obtained over surfaces having departures of hundreds of visible wavelengths from a reference surface The disclosed technique avoids cumulative summing of detector errors over a large detector array by computing the "equivalent" phase for each detector independently of the intensities of other detectors Inaccurate phase data points having an equivalent fringe contrast less than a predetermined threshold are eliminated from data from which contour maps of the aspheric surface are displayed or plotted

Journal ArticleDOI
TL;DR: To use separated telescopes to achieve diffraction-limited performance over a finite field of view, the following rule must be obeyed: as viewed from a point in the focal plane, beams from separated telescopes must be recombined so that they appear to be coming directly from a single large telescope which has been masked so as to reproduce exactly the ensemble of collecting telescopes.
Abstract: In the present paper, work is discussed which arose in the context of optical design studies for the proposed space-based COSMIC (Coherent Optical System of Modular Interferometric Collectors) telescope. The operation of COSMIC involves the combination of a number of parallel beams with a central beam-combining telescope which forms an image of the sky. The paper is mainly concerned with the aspects of beam combination. The paraxial constraint condition is considered along with tolerances regarding the individual optical elements, and imaging as a nonshearing recombination. A first-order requirement for achieving a finite field of view is discussed, taking into account specifically the case of a coherent imaging optical system.


Journal ArticleDOI
TL;DR: It is shown that these corrections can be important, reducing the apparent source size by 20% and coherence effects are shown to significantly reduce the coherence parameters for small sources.
Abstract: The effects of coherence and final-state Coulomb interactions on the Bose-Einstein correlations of identical particles are studied. It is shown that these corrections can be important, reducing the apparent source size by 20%. Coherence effects are shown to significantly reduce the coherence parameters for small sources. Other causes of correlation are also discussed.

Journal ArticleDOI
TL;DR: In this paper, a 2.66-MHz radar operated as an imaging Doppler interferometer was used to make measurements in the 60-100 km region using a two-dimensional image of the scattering surface.
Abstract: We have made measurements in the 60–100 km region using a 2.66-MHz radar operated as an imaging Doppler interferometer. This allows us to view the entire region within 24° of zenith simultaneously, Doppler-sorting and then echo-locating the returns to achieve image resolution of ±3° in zenith angle and ±5 m/s in velocity. The approach is contrasted with conventional beam-forming radar methods. We assume that the phenomena responsible for the observed weak radar scattering can be described as a distribution of discrete scattering points. Each scattering point is then characterized by its three spatial coordinates, its radial velocity, and the amplitudes and phases of its spectral components measured on a number of independent antennas. We present a series of apparent-motion profiles from 61 to 87 km, showing the repeatability of the profiles and their evolution in time, followed by a two-dimensional image of the scattering surface at 85 km, showing the motions of the individual scattering points and their distribution in space. Then we show images of the scattering surfaces from altitudes of 58 to 103 km, every 9 km, showing at each altitude the distribution in the horizontal plane of the locations of the scattering points, the specularity, or aspect sensitivity, of the scattering, and the derived apparent-motion vectors. A sequence of eight 51-s frames shows highly structured activity at 103 km.

Journal ArticleDOI
TL;DR: A theoretical analysis of the measurement accuracy in sinusoidal phase modulating (SPM) interferometry shows clearly that SPM interferometer has a high measurement accuracy of the order of 1 nm.
Abstract: A theoretical analysis of the measurement accuracy in sinusoidal phase modulating (SPM) interferometry is presented. The measurement accuracy is dependent on multiplicative and additive noise. The characteristics of SPM interferometry in the presence of this noise are made clear. Theoretical results show clearly that SPM interferometry has a high measurement accuracy of the order of 1 nm.


Journal ArticleDOI
J. Kuhl1, J. Heppner1
TL;DR: In this article, the group velocity dispersion of a multilayer thin film Gires-Tournois interferometer used for reflection of ultrashort optical pulses can be continuously tuned from positive to negative values at an extremely low loss in pulse energy.
Abstract: The group velocity dispersion of a multilayer thin film Gires-Tournois interferometer used for reflection of ultrashort optical pulses can be continuously tuned from positive to negative values at an extremely low loss in pulse energy. Thus, this device can be applied for compression of femtosecond pulses independent of the sign of the frequency chirp by simple angle tuning of the interferometer. This has been demonstrated with up-chirped 210 fs pulses which have been compressed to an almost transform-limited duration of 115 fs.

Journal ArticleDOI
TL;DR: In this article, a Michelson interferometer has been used as a direct quantitative probe for gas phase plasma formation in the UV excimer laser ablation of solids, and the thresholds for plasma formation are determined and correlated with optical emission from electronically excited ablation fragments.
Abstract: A Michelson interferometer has been used as a direct quantitative probe for gas phase plasma formation in the UV excimer laser ablation of solids. Excimer laser fluence thresholds for plasma formation are determined and correlated with optical emission from electronically excited ablation fragments.