Fringe Intensity Research Articles

Quantum theory of combined first order/second order optical interference experiments

The quantum theories of two recently-proposed optical interference experiments are presented. It is shown that the measured signal is sometimes equal to a product of a first-order fringe intensity with a degree of second-order coherence. The experiments do not provide any useful basis for discriminating between the quantum and classical theories of light.

Third-order optical susceptibility determination by third harmonic generation. I

A method for determining the third-order nonlinear susceptibility of liquids using third harmonic generation (THG) is presented. A review of molecular polarizability and discussion of the relationship to susceptibilities are presented. All materials, including air and windows of the liquid cell, can make substantial contributions to the total THG intensity; this technique accordingly accounts for their effects. The method relies on use of a cell with wedged windows and a wedged liquid chamber which when placed in a vacuum chamber and translated across the optical path generates complex THG intensity fringes. By analysis of the latter, the liquid susceptibility is extracted. Several simple neat liquids are used to demonstrate the method.

Coherent image fringe contrast measurement with sensing arrays

Two methods are described for measuring interferometric fringe contrast with sensing arrays. The absence of air turbulence allows contrast to be determined quickly by measuring the intensity of the fringe pattern at phases 90° apart. The presence of turbulence requires that the peak-to-peak fringe intensity be found by sampling the fringes as they are scanned across the array. An analysis is presented showing the relation between maximum error in fringe contrast measurement and the number of samples taken. Experimental results are presented which show the effect of turbulence on fringe contrast measurement.

Metre Wavelength Solar Radio Bursts with Periodic Modulation

Observations of solar radio bursts in the frequency range 125-150 MHz are described. It is found that their properties are consistent with those observed for similar bursts in the 30-55 MHz range, except that all, rather than just a small proportion, showed periodic intensity maxima or fringes in the frequency-time plane. Fringe separation ?f was found to change with frequency between 30 and 150 MHz according to ?f 8 f 1.48, a result inconsistent with Faraday rotation as the cause of the fringes.

Three-beam effects inPendellösungfringes

The perturbations of standard two-beam Pendellösung fringes due to simultaneous excitation of an additional Bragg beam have been studied. For a qualitative understanding of the observed local changes in both fringe position and intensity, a plane-wave description has proved to be sufficient. Through three-beam calculations of Bloch-wave excitation coefficients it is found that the main intensity terms may be ascribed to the same four dispersion surface branches which are excited also in the corresponding two-beam case. The continuous variation observed in the fringe period and position is explained from the variation in the width of the dispersion surface gap. This gap varies with the sign and size of the deviation parameter of the simultaneously excited beam. For a given deviation parameter the gap width also depends on the sign of the product between the three structure factors involved. The resulting dependence of the fringe displacement on this sign may be utilized to determine the three-phase structure invariant experimentally.

うずまきシャッタを使用したホログラフィ干渉法 (第3報)

When the movement of an object moving toward a hologram plate with constant velocity is recorded by the methods of holographic interferometry using a swirl type shutter, the intensity of a reconstructed image of the object changes according to velocity of an object, exposure time and observational aperture. The above phenomena were analyzed and confirmed by the experiment. The distinctness of the fringe was defined as the differ-ence between the fringe intensity of maxima and minima. By this standard the optimum experimental condition was obtained. On the basis of the above investigations, the standardization of the experimental procedure was shown.

Quantum interference and the quantum potential

We re-examine the notion of the quantum potential introduced by the Broglie and Bohm and calculate its explicit form in the case of the two-slit interference experiment. We also calculate the ensemble of particle trajectories through the two slits. The results show clearly how the quantum potential produces the bunching of trajectories that is required to obtain the usual fringe intensity pattern. Hence we are able to account for the interference fringes while retaining the notion of a well-defined particle trajectory. The wider implications of the quantum potential particularly in regard to the quantum interconnectedness are discussed.

Intensity Modulation Produced by Crossed Electric and Magnetic Field Electron Image Deflection Systems

It was found that intensity fringes were produced in a crossed electric and magnetic field electron image deflection system. The origin of these fringes is discussed.

Mass diffusion measurements in liquid crystals by a novel optical method

Binary mass diffusion measurements have been performed in fluid media doped with photochromic dye molecules. A periodic concentration of tagged molecules is created by illuminating the sample with a fringe intensity pattern. The photo induced change of refractive index and/or absorption of the dye molecules creates an optical grating which is observed through Bragg diffraction of an auxiliary laser beam. When the flash excitation is switched off, this grating will relax since photoexcited molecules will diffuse into nonphotoexcited zones and vice versa. The main advantages of this method are that: (1) the duration of the experiment is strongly reduced compared to classical tracer methods since diffusion lengths, defined by the fringe spacing, are small (1–100 μm); (2) the possibility of studying anisotropic diffusion is readily available; and (3) small sample volumes are required. Results are reported on the diffusion of methyl red in a homogeneously aligned sample of MBBA. In the nematic phase, the diffusion is faster along the local optical axis than perpendicular, the anisotropic ratio D∥/D⊥ being 1.6±0.1 at 22 °C, in good agreement with previous tracer data. The temperature dependence yields an activation energy of 5.8±0.7 kcal/mole for D∥ and 6.0±0.8 kcal/mole for D⊥. In the isotropic phase, the activation energy is found to be 10±1.5 kcal/mole.

An Analysis on Fringe Formation in Holographic Interferometry

Formation of interference fringes in the holographic measurement of displacement distribution on a rough surface or flow velocity distribution on a section plane in a fluid is analysed using the concept of random process and the stationary phase method. The displacement or velocity is assumed to vary slowly on the surface. Restrictions are not severe in other respects: the rough surface may be curved; the illumination wave need not be plane; the entrance pupil of the observing optical system may be located at a finite distance from the object; many types of holographic interferometry such as multiple-exposure or time average method are taken into consideration. The analysis is made for two cases: one is when the observation point is far from the rough surface and the other is when it is far from the entrance pupil of the observing system, including the observation near the rough surface. In the former case the resultant intensity at the observation point can be considered as the superposition of the constituent fringe intensity arising from the displacement of each contributing point on the rough surface. In the latter case the intensity can be obtained as the integral of the contributing part of the constituent fringe intensity over the entrance pupil.

The central fringe in two-beam interferometers with division of amplitude

If uncompensated differences of light paths in dispersive media are excluded, the appearance of the central fringe is determined by changes in phase and amplitude caused by reflexions and transmissions on surfaces and layers of the interferometer components. The central position in the fringe system, which is not confined to a maximum or a minimum of the fringe intensity, is found to be the derivation of the argument of the complex visibility with respect to the wavelength. The determination of the central position is discussed with some simple interferometers as examples.

Variation of Electron Microscopic Thickness Fringes of Aluminium Single Crystals with Energy Loss

From the observation of energy-filtered thickness fringes in electron microscopic bright-field and dark-field images of thin aluminium single crystal films it is found that (1) the fringe positions and distances are almost the same regardless of the filter potential, and (2) the fringe intensities of no-loss, 7 and 15 eV loss electrons decrease slowly as the thickness increases but those of 3 and 10 eV loss electrons decrease rapidly. These effects are explained by using a n -slice dynamical theory in which the effect of energy losses is taken into account.

Homodyne Electrophoretic Light Scattering of Polystyrene Spheres by Laser Cross-Beam Intensity Correlation

Homodyne light fluctuation spectroscopy is combined with an electrophoresis apparatus to provide a technique that rapidly measures electrophoretic mobilities of charged particles suspended in a liquid medium. Two parallel laser beams, polarized in the same direction, are focused into a scattering cell by a cylindrical lens. The laser beams interfere at the focal point of the lens to produce a fringe intensity profile. As scattering particles are driven through the fringes, the scattered light intensity is modulated. This modulation is detected by digital autocorrelation of photoelectron pulses from a photomultiplier. With this technique the electrophoretic mobility of 1-micro diam monodisperse polystyrene spheres was determined to be 4.6 +/- 0.2 (micro/sec)/(V/cm) in water.

Propagation of a high-intensity laser pulse with small-scale intensity modulation

For laser beams of large aperture with power far above the critical power for self-focusing, nonlinear propagation instabilities lead to the growth of small-scale variations in intensity and phase. We report measurements of the growth rate for interference fringes in unpumped ED-2 laser glass as a function of fringe spacing and intensity. Calculations based on the simplest form of linearized small-scale instability theory agree approximately with the measured rates, and a more complete linearized treatment predicts the growth rates within experimental error.

A short-gage-length optical gage for small strain

This paper describes a method of increasing the sensitivity of interferometric surface-strain measurement. The new technique utilizes the fact that the interference pattern has a region in which the fringe motion is linearly related to the fringe intensity. The theory of this linear gage, a description of measurement techniques, and the results of evaluative experiments are presented.

The stacking fault energy in the vicinity of a coherent twin boundary

Abstract The stacking fault energy in the vicinity of a coherent twin boundary is measured, in zone-refined copper and in copper with 0–18 at. % cobalt, by the dissociation of dislocations and the intensity of the fault fringes. The results suggest that the stacking fault energy in the slip planes next to the coherent twin boundary is about 2% of the stacking fault energy of the bulk material and increases with increasing distance. Intrinsic and extrinsic stacking faults may be formed in the crystal lattice close to the boundary.

Measurement of deposition rate in matrix spectroscopy with a small laser

A set-up is reported for measurement of the deposition rate of transparent matrix materials typically used in matrix isolation spectroscopy. Its main features consist in measurement of intensity of interference fringes produced by the growing matrix layer on the light of a small laser by a simple power meter. A typical example for an Ar matrix is shown.

Intensity of Diffraction and Interference Fringes

Intensity of Diffraction and Interference Fringes

Use of the Babinet Compensator for Anomalous Dispersion Measurements

Reorientation of the optical elements in a standard experimental setup that utilizes a Babinet compensator to measure the anomalous dispersion of a birefringent mediumn results in a useful trade-off between the intensity and visibility of the polarization fringes produced by the apparatus. The fringe pattern is analyzed and numerical results are presented that illustrate the nature of the trade-off and its application to measurements near the center of a strong absorption line.

The Fresnel Hologram of a Square Aperture

A simple analytical method is presented for the complete prediction of the interference pattern of a square aperture as recorded by a hologram in the near field. Graphical means are used to evaluate the resulting Fresnel integrals and to locate the fringe positions and intensities. The resulting exercise is considered a valuable tutorial device for the understanding of the holographical phenomenon.