Stationary Fizeau fringes, phase shift interferometric fringes, fringes obtained in Murty lateral shear interferometry, vibration interference pattern as seen by digital speckle pattern interferometer all are digitally captured in specific interferometer set- ups. IntelliWave software produced by Engineering Synthesis Design, Inc. (ESDI) is used to process the fringe patterns. For all these fringe patterns the physical principle and set up for obtaining them are described. This could be a resume for student and young researcher guiding in experimental interferometry.
A spatial light modulator is a matrix-shaped device able to modify the amplitude or the phase of the reflected or
transmitted light, which can be operated pixel by pixel independently. This opens new possibilities for rapid and efficient
manipulation of the light diffraction but also brings us close to the ambiguous boundary between physical and digital
optics, or more precisely between the continuous and the discrete mathematical approaches of diffraction. In this article
we show a series of diffraction experiments in which we use the modulator to simulate various optical elements,
physically real or not, recorded real or computed holograms, experiments in which due to the discrete nature of the
modulator we are liable to use alternately the discrete and the continuous approach. To avoid ambiguities we have to
keep track of the approaches we use, and also, more importantly, to be able to switch from discrete to continuous terms
In this paper we describe a traceable to the meter standard method to measure the height of an artifact used as a calibrator for observation instruments in nanotechnologies and nanosciences. The artifact is a grating specially manufactured so that its features (height, pitch, width, wall angles) are highly uniform across its area. A Linnik microscope designed for longitudinal (vertical) measurements using the principle of white light interferometry was used to determine the height of the grating. To insure the traceability of the measurements a laser source of known wavelength was used and the measurements obtained using white light were calibrated to it. The experimental data was statistically analyzed and the measurement precision was estimated to be in the range of nanometers. The data were compared with the results obtained using the TIC method with a Carl Zeiss microscope.
In this paper a Fourier transform digital holography experimental arrangement is presented. It is actually a hybrid
arrangement, half digital half analog. The Fourier hologram was constructed using the analogous means of the so called
lensless configuration. The hologram was recorded digitally by a camera with a large CCD array in stead of the
recording medium. The recording of the image was analyzed with a computer and the original image was reconstructed
by means of the discrete Fourier transform.
The paper presents measurements of magnetic liquids shaping by use of magnetic fields or gravitation and centrifugal
forces. These measurements are conducted with the goal of evaluating the characteristics of the magnetic fluids in order
to obtain an adaptive system. Values of frequency response domain, pattern imposed configuration response, and free
surface curvature were measured. Three types of optical arrangements were used to determine the parameters: schlieren,
Fizeau type interferometer and triangulation optical scheme.
In this paper a simple method for determining the wavelength of an unknown source, (a problem of great theoretical and
practical importance), based on the Moire fringes phenomenon and Fourier analysis is presented and put into practice.
The accuracy and the simplicity of the problem makes it attractive and competitive.
We discuss an experiment for detecting small deformations by speckle interferometry. Vibration modes of an
aluminium plate are observed by digital speckle pattern interferometry (DSPI). A Mach-Zender interferometer
arrangement is used and the speckle interferograms are recorded with a CCD camera and processed on a computer.
These fringes depend on the path differences due to the vibration of the aluminium plate from its original state.
Vibration amplitudes between 0.3-0.6 &mgr; were measured for seven vibration modes.
In this paper we investigate the vibrations of a square aluminium plate by speckle interferometry means. Modes of
vibration of this plate are shown as speckle interferograms. As usually is the case with such interferograms, enhancement
and filtering of these images is needed after recording. The speckle index and the signal-to-noise ratio (SNR) of the preprocessed
interferograms before and after filtering are calculated. An improvement of the SNR between 1.37 and 1.81 is
obtained for the vibration modes presented here.
This paper is concerned with the determination of in-plane displacements and deformations, by using digital speckle
correlation. A special algorithm for determining the position of the maximum of the correlation function is presented. An
example on how to apply this method is presented.