scispace - formally typeset
Search or ask a question

Showing papers on "Interferometry published in 1978"


Journal ArticleDOI
TL;DR: In this paper, a detailed discussion of the origin and spatial anisotropy of refractive-index nonlinearities is presented, and methods for measuring the nonlinear refractive index coefficient are reviewed.
Abstract: The propagation of intense optical beams through dielectric media induces changes in the refractive index which cause self-focusing and beam breakup in high-power laser systems. After a brief discussion of the origin and spatial anisotropy of refractive-index nonlinearities, methods for measuring the nonlinear refractive index coefficient are reviewed. The use of time-resolved interferometry is described in detail. Nonlinear indices for optical glasses and crystals measured at 1064 nm by this technique are tabulated. From these data, an empirical expression is given which, using the linear refractive index and partial dispersion, provides a good estimate of the nonlinear index of optical materials in the long-wavelength limit.

229 citations


Journal ArticleDOI
TL;DR: In this article, a Fabry-Perot interferometer filled with a medium whose refractive index depends upon intensity has a multiple-valued transmission-vs-intensity characteristic.
Abstract: A Fabry-Perot interferometer filled with a medium whose refractive index depends upon intensity has a multiple-valued transmission-vs-intensity characteristic. When the incident light is circularly polarized, and the nonlinearity is only cubic in the fields, Maxwell's equations may be solved exactly for the plane-parallel resonator field in terms of elliptic functions. An accurate approximate analysis is given for more general cases, including resonators with spherical mirrors and finite beams, where self-focusing is important. The theory is developed to yield design information for operation as an optical switch, "transistor," and power limiter.

227 citations


Journal ArticleDOI
TL;DR: A wideband laser-interferometer gravitational-radiation antenna was constructed and used to search for gravitational radiation in the frequency band from 1 to 20 kHz as discussed by the authors, where the antenna consisted of a Michelson interferometer with the beamsplitter and retroreflectors attached to masses on soft suspensions that allowed essentially free motion above the suspension frequencies.
Abstract: A wideband laser-interferometer gravitational-radiation antenna was constructed and used to search for gravitational radiation in the frequency band from 1 to 20 kHz. The antenna consisted of a Michelson interferometer with the beamsplitter and retroreflectors attached to masses on soft suspensions that allowed essentially free motion above the suspension frequencies. The strains in the gravitational radiation produce a differential path length change in the two arms of the interferometer which is detected by a pair of balanced photodetectors. The interferometer used a folded-path configuration with an effective length of 8.5 m. The sensitivity of the interferometer was calibrated with signals from a piezoelectric displacement transducer. The strain noise in a 1-Hz bandwidth was less than 0.3 fm/m from 1 to 3 kHz, and less than 0.1 fm/m above 3 kHz, where it was essentially photon-noise limited. (For comparison, the $\mathrm{kT}$ strain noise in a room-temperature, 2-m long, 1000-kg, elastic solid bar antenna is 0.14 fm/m.) The laser interferometer was operated as a detector for gravitational radiation for 150 h during the nights and weekends from the period 4 October through 3 December 1972. During the same period, bar antennas were operated by the Maryland, Glasgow, and Frascati groups, with 18 events reported by the Frascati group in their single bar, 22 single-bar events and no coincidences reported by the Glasgow group in their two bars, and 28 coincidences reported by the Maryland group between the Argonne bar and the Maryland bar and/or disk antennas. The various bar antenna systems were quite different but in general were sensitive to gravitational-radiation strain spectral components with an amplitude of the order of 0.1 fm/m in a narrow band of frequencies about the resonant frequency of the bar. The wideband interferometer data was analyzed by ear, with the detection sensitivity estimated to be of the order of 1-10 fm/m (depending upon the signature of the signal) for the total of the gravitational-radiation strain spectral components in the band from 1-20 kHz. No significant correlations between the Malibu interferometer output and any of the bar events or coincidences were observed.

179 citations


Patent
Peter W. Smith1
03 May 1978
TL;DR: In this article, a nonlinear interferometer is described where a Fabry-Perot cavity is substantially filled with an electro-optic material having terminals to which a potential can be applied, and a beam splitter at the output of the cavity deflects a portion of the optical energy coming from the cavity.
Abstract: A nonlinear interferometer apparatus is disclosed wherein a Fabry-Perot cavity is substantially filled with an electro-optic material having terminals to which a potential can be applied. A single frequency, single mode, linearly polarized source of optical radiation is coupled into the cavity and a beam splitter at the output of the cavity deflects a portion of the optical energy coming from the cavity. This deflected portion of output optical energy is incident on a photodetector whose output is amplified and connected to the terminals of the electro-optic material. The resulting device exhibits differential gain, and can function as an optical switch, limiter or optical memory element. With sufficient amplification of the detector output, an optical quantizer is provided. By properly adjusting the cavity length and providing a substantially constant optical signal to the input end of the cavity, an amplified replica of an amplitude modulated optical signal applied to the photodetector appears at the output end of the cavity.

117 citations



Journal ArticleDOI
TL;DR: In this paper, Hanbury Brown and Davis measured the angular diameters of the 32 brightest blue stars in the southern hemisphere using a pair of holes, which was the first measurement of stellar angular diameter.
Abstract: Stellar interferometry may be defined as the art of utilizing interference effects for improving the angular resolution of stellar observations. Resolution is improved in two ways: (a) interferometers attached to conventional telescopes can approach the diffraction limit of resolution, which is not accessible to ordinary observation with large telescopes owing to atmospheric turbulence, and (b) because interferometers can have base­ lines appreciably larger than the size of monolithic mirrors, their resolu­ tion is subject to improvement in proportion. Improving the angular resolution of optical observations has been a dream of astronomers from the time of William Herschel, when it became clear that image sharpness was limited by the atmosphere rather than by telescope optics. Following Fizeau's idea of observing through a pair of holes, ways in which the atmospheric limitation could be overcome were brilliantly demonstrated by Stephan (1873), Michelson ( 1920), and more recently Hanbury Brown (1974). Not only were these pioneers able to approach the diffraction limit in large telescopes, but they also succeeded in reducing this limit further by increasing the baseline spans beyond the size of telescope apertures. Pease's observation of the brightest red stars provided the first measure­ ments of stellar angular diameters. With still higher resolution, R. Hanbury Brown and 1. Davis were able to resolve and measure the angular diameters of the 32 brightest blue stars in the southern hemisphere. For both red and blue stars, angular diameters provide direct informa­ tion on how much the object deviates from a black-body source. Indeed, black bodies of given temperature, or color, and apparent magnitude have a predictable apparent size that can be checked against observation. Diameter excess may indicate an absorbing envelope, or temperature

99 citations


Journal ArticleDOI
TL;DR: In this article, a self-aligning interferometer was developed using a dual polarization Zeeman stabilized He-Ne laser, which can be recovered by heterodyne detection through a separate reference-frequency mode.
Abstract: The field backscattered from a remote surface into the laser cavity induces an efficient modulation, both in amplitude and frequency, of the cavity field. The modulating signals are the interferometric components (sin and cos) of object optical path length, which can be recovered by heterodyne detection through a separate reference‐frequency mode. Using a dual polarization Zeeman stabilized He‐Ne laser, a compact self‐aligning interferometer is developed.

99 citations


Journal ArticleDOI
TL;DR: In this paper, a polarization interferometer employing free standing wire grid polarizer and beamsplitter and reflection dispersive Fourier transform spectrometry is used to determine the optical constants of water in the region 5-220cm −1.

95 citations


Journal ArticleDOI
TL;DR: In this paper, a far-infrared polarimeter is combined with a Veron-type interferometer to yield the line integrals in a plasma simultaneously along the same probing beam.

88 citations


Proceedings ArticleDOI
15 Dec 1978
TL;DR: In this paper, two methods are presented for sensitive measurement of non-reciprocal phase shift (NRPS) in a multi-turn fiber Sagnac interferometer for application in inertial rotation sensing.
Abstract: Two methods are presented for sensitive measurement of nonreciprocal phase shift (NRPS) in a multi -turn fiber Sagnac interferometer for application in inertial rotation sensing. Both techniques are capableof producing an NRPS modulation of amplitude ± r radians at a rate sufficiently high for shot -noise - limitedperformance. The first method produces an NRPS by generating a nonreciprocal refractive index using theelectro -optic effect, and requires orthogonal polarization in the cw and ccw beams. The second method produces an NRPS by generating a nonreciprocal propagation frequency using two acousto -optic shifters;there is no requirement on light polarization. When either method is used in conjunction with phase- sensi-tive detection, feedback compensation, and adequate laser intensity, shot -noise -limited measurement be- comes possible. Preliminary performance data is included. Introduction Currently there is considerable interest in using a multiturn fiber Sagnac interferometer for the mea-surement of inertial rotation.l Such a measurement is difficult to perform because the nonreciprocal phaseshift (NRPS) induced in the fiber by inertial rotation is very small. For a rotation rate SZ, the NRPS 04) is

67 citations


Journal ArticleDOI
TL;DR: In this article, the incorporation of a pulsed ruby laser into an electronic speckle pattern interferometer was described for observing vibrational and transient events with a double pulsed laser and some typical results were given.
Abstract: This paper describes the incorporation of a pulsed ruby laser into an electronic speckle pattern interferometer. A technique is described for observing vibrational and transient events with a double pulsed laser and some typical results are given. Results of the application of the interferometer to non-destructive testing are included.

Journal ArticleDOI
TL;DR: In this article, a modified version of the moving mirror wavelength measuring interferometer has been used for cw laser interferometry and its accuracy has been experimentally confirmed to one part in 108.
Abstract: We report on a modified version of our previous moving mirror wavelength measuring interferometer. Its accuracy has been experimentally confirmed to one part in 108. The device is simple and seems ideally suited for cw lasers.


Journal ArticleDOI
TL;DR: In this article, the uncertainty principle was used to set one limit to the sensitivity for detection of such displacements by a linear position-sensing system such as an optical interferometer.
Abstract: Detection of gravitational radiation by some form of Michelson interferometer illuminated by a laser depends on observing the small relative displacements or forces which would be induced in test masses by a gravitational wave. The uncertainty principle would appear to set one limit to the sensitivity for detection of such displacements by a linear position-sensing system such as an optical interferometer. The authors discuss this limit, and also show how one method of treating photon statistics and photon recoil effects yields a similar limit. This is done in the spirit of the 'Heisenberg microscope'.


Journal ArticleDOI
TL;DR: A method by which the frequency shift equals 4N times the rotation rate, where N is the number of rotating components available, and a higher heterodyne frequency is possible than with the previously described techniques is described.
Abstract: Twyman-Green. This Letter describes a method by which the frequency shift equals 4N times the rotation rate, where N is the number of rotating components available. The advantage of this method over previously described methods is that a higher heterodyne frequency is possible than with the previously described techniques. Let the light entering an interferometer, shown in Fig. 1, be separated into two orthogonal linear polarizations using, for example, a polarization beam splitter P. Each component travels a separate path through the interferometer cavity seeing a different optical phase retardation. Upon recombination the light passes through the frequency shifter and onto a detector plane, where the temporally varying optical signal has a phase equal to the net phase difference between the two paths inside the interferometer. The frequency shifter, which we shall describe using Jones calculus 3 and the complex wave representation of light, consists of a stationary quarterwave plate (QS) followed by a series of rotating halfwave plates (Hr) separated by stationary halfwave plates (HS), followed by a stationary linear polarizer (LS). The following analysis demonstrates a frequency shift of eight times the rotation rate of the halfwave plates. We begin by treating the horizontal (X) component, which we represent by

Journal ArticleDOI
TL;DR: In this article, a tilt-compensated triple-pass system for use with previously built Fourier spectrometers to increase the resolution by 3 is described. But the resulting width of the apparatus function of the third-generation interferometer is better than 10−3 cm−1 and can be meaningfully expressed in frequency units.
Abstract: The contribution of the third-generation Fourier spectrometer, built at the Laboratoire Aime Cotton and currently at the Laboratoire d'Infrarouge, to meteorological and high resolution Doppler-limited measurements is reported citing typical examples and the latest instrumental improvements. A tilt-compensated triple-pass system for use with previously built Fourier spectrometers to increase the resolution by 3 is described. The resulting width of the apparatus function of the triple-pass third-generation interferometer is better than 10−3 cm−1 and can be meaningfully expressed in frequency units. Its actual value is 27 MHz. For the first time a spectrometer is able to give very wide spectral range information with a resolving power sufficient to analyze sub-Doppler spectra.

Journal ArticleDOI
TL;DR: It is shown that the PDI is simple and easy to use and also yields fringes of constant optical path difference similar to those obtained with a Twyman–Green interferometer.
Abstract: A point-diffraction interferometer (PDI) for use in the infrared is discussed. It is shown that the PDI is simple and easy to use and also yields fringes of constant optical path difference similar to those obtained with a Twyman–Green interferometer. The fabrication of the PDI is described, and typical results obtained using the interferometer at a wavelength of 10.6 μm are shown.

Journal ArticleDOI
TL;DR: An optical heterodyne interferometer utilizing a fiber optic target probe and a digital phase compensation system and the effect of background motions on output is described.
Abstract: An optical heterodyne interferometer utilizing a fiber optic target probe and a digital phase compensation system is described. Optical performance and the effect of background motions on output are described. Maximum sensitivity for a simulated biological target in aqueous medium is 0.05 A Hz−1/2 for a signal‐to‐noise ratio of unity.

Journal ArticleDOI
TL;DR: In this article, a number of beam-splitter designs utilizing thin metal films are discussed, and it is shown that, using conventional techniques, the required phase difference can be readily achieved using, for example, combinations of gold, chromium and aluminium films.
Abstract: The measurement of displacement using a Michelson-type interferometer requires a beam-splitter coating that ideally produces two signals in phase quadrature. In this paper a number of beam-splitter designs utilizing thin metal films are discussed. Problems associated with film deposition and monitoring are considered, and it is shown that, using conventional techniques, the required phase difference can be readily achieved using, for example, combinations of gold, chromium and aluminium films.

Journal ArticleDOI
TL;DR: In this article, the authors considered an n-level atom and showed that two relevant levels a and b with the same pari ty can be coupled by two-photon processes via all the other intermediate levels of suitable pari-ty to satisfy the selection rules for one-poton processes.
Abstract: Optical bistabflity as a kind of first-order phase transition has been suggested and experimentally observed in an optical feedback system (1) as well as in a resonant absorber within an interferomcter ([ 2). A multiple-pass interferometer with a suitable nonlinear dispersive or absorptive mechanism can behave as a bistable optical system. The first suggestion was made by SZ6K~ et al. (1), and different versions have been shown to work with the nonlinearity due either to an atomic medium at resonance with the impinging field (2) or to an external feed-back system (3). We are here interested in the optical bistability arising from the collective behaviour of an atomic system. A general theory has been formulated in a series of papers by BONIFACIO and LVGIATO (4) to obtain absorptive and dispersive atomic bistability. As is well known from the first approaches (3) a difficulty of atomic bistability consists in inhomogeneous broadening due to the Doppler contribution of atom in a cell. We show here evidence of a bistable behaviour of an interferometer filled with a two-photon absorber and working in a travelling wave mode. This is the first step to derive, afterwards, a Doppler free atomic bistability (6) by absorbing photons from opposite directions and getting rid of the inhomogeneous line. We consider an n-level atom (fig. 1) where two relevant levels a and b with the same pari ty can be coupled by two-photon processes via all the other intermediate levels of suitable pari ty to satisfy the selection rules for one-photon processes. We introduce an interaction with a classical field that we write in the slowly varying envelope approximation as


Journal ArticleDOI
TL;DR: A two-wavelength plasma density interferometer utilizing a CO(2) laser and an HeNe laser is described, being designed for use on Doublet III, a large noncircular cross-section tokamak.
Abstract: A two-wavelength plasma density interferometer utilizing a CO(2) laser and an HeNe laser is described. The interferometer is being designed for use on Doublet III, a large noncircular cross-section tokamak. The use of the two wavelengths allows the distinction between fringe shifts due to plasma density and fringe shifts due to mirror vibrations. Plasma density fringe shifts of 1/10 of a fringe shift can be measured in the presence of mirror vibrations which cause several fringe shifts. A simple digital phase comparing electronic system is used.

Book ChapterDOI
01 Jan 1978

Journal ArticleDOI
TL;DR: The basic characteristics and instrumentation of the experimental interferometer setup at the Institut Max von Laue - Paul Langevin (I.L.L.), Grenoble are outlined in this article.

Journal ArticleDOI
TL;DR: The current status of holography and its applications with some historical background to place the current activity in perspective is discussed in this article, where basic types of holograms are described together with their properties.
Abstract: The current status of holography and its applications are discussed with some historical background to place the current activity in perspective. Basic types of holograms are described together with their properties. Applications in optical image formation include photography, microscopy, image storage and image replication. Acoustic, X-ray, electron beam and microwave holography are briefly commented upon. The second major area of application is contour generation and interferometry. Finally, the current status of holographic optical elements is assessed.

Journal ArticleDOI
TL;DR: This paper discusses the use of Michelson interferometers in the study of transients, and new results will be presented.
Abstract: Fourier transform spectroscopy has been demonstrated to provide outstanding results in astronomical and high resolution spectral studies of cw sources. However, techniques for the study of reacting or transient systems have been less than satisfactory in cases where one is seriously interested in obtaining detailed spectroscopic data. It has been demonstrated that Fourier transform techniques can also be utilized in the study of systems which are transient as well. This paper discusses the use of Michelson interferometers in the study of transients, and new results will be presented.

Journal ArticleDOI
TL;DR: An interferometer has been developed with which it is possible to make simultaneous measurements of plasma density along several chords with unambiguous and uniformly sensitive readings.
Abstract: An interferometer has been developed with which it is possible to make simultaneous measurements of plasma density along several chords. A single Bragg cell and laser are used, and the phase detection is in quadrature in order to obtain unambiguous and uniformly sensitive readings.

Journal ArticleDOI
TL;DR: A method of aligning the Michelson polarizing interferometer which optimizes its performance is given and may be used to measure the optical transfer function of a component in the output beam as a function of both spatial and optical frequency.
Abstract: A detailed analysis is presented of the Michelson polarizing interferometer suggested by Martin and Puplett. This instrument has many favorable properties for use as a far ir Fourier spectrometer. The effect of misalignments and imperfections of the optical components on the instrumental performance is calculated. Based on these results, we give a method of aligning the interferometer which optimizes its performance. In addition, this instrument may be used to measure the optical transfer function of a component in the output beam as a function of both spatial and optical frequency. A procedure is described by which this may be done.

Journal ArticleDOI
E. O. Schulz-DuBois1, P. Wolf1
TL;DR: In this paper, the authors investigated the range in operating currents for which a Josephson interferometer, sometimes referred to as Superconducting QUantum Interference Device (SQUID), may remain in the zero-voltage Josephson condition.
Abstract: This investigation deals with the range in operating currents for which a Josephson interferometer, sometimes also referred to as Superconducting QUantum Interference Device (SQUID), may remain in the zero-voltage Josephson condition. An interferometer consists of one or more inductive loops each of which contains two Josephson junctions or other weak links. Two types of current are considered. Gate currentIgpasses the junctions in parallel. Control currentIcgenerates magnetic flux via inductive coupling in the loops. Zero-voltage operation is possible within certain areas of theIg,Icplane. These areas are manifestations of flux-quantum states and their boundary lines are referred to as static characteristics. In view of the nonlinearity of the constituting equations, not all their formal solutions are physically realizable. A stability analysis yields criteria which permit the identification of realizable operating conditions. The static characteristics comprise operating conditions where the limit of stability is reached. To obtain the static characteristics, linearized equations may be utilized if theLIo product, a measure for the size of an interferometer, is large compared to the flux quantumΦ0, whereL is the inductance per loop, andIo the maximum Josephson current per junction. As a general method of solving system of transcendental equations, continuation is discussed. The utilization of continuation for obtaining interferometer characteristics is explained. It is shown that some changes in the gate-current feed arrangement are equivalent to shearing the characteristics in theIg,Icplane. Analytical results are given on extrema, inflexion points, and singularities in the shape of cusps which conceptually relate to the existence and connectivity of flux-quantum states. Experimental static characteristics are presented on two-and four-junction interferometers. They are in agreement with characteristics computed on the basis of simple lumped circuit models. Relevant circuit parameters are obtained from the experimental characteristics.