Showing papers by "Giovanni Pierattini published in 1999"
ARCO1
TL;DR: A new, folded reversal interferometer is presented, based on the reflective grating interferometers, which can be applied for optical isolation and testing of coma aberration and has several advantages in respect to other existing optical reversal configurations.
Abstract: We present a new, folded reversal interferometer. It is based on the reflective grating interferometer and can be applied for optical isolation and testing of coma aberration. The interferometer has several advantages in respect to other existing optical reversal configurations. A carrier can be easily added for phase retrieval in interferometric fringe patterns for mapping coma aberration. Furthermore, in an asymmetric optical configuration a lateral shear can also be added, transforming it in a reversal shearing interferometer. The principle of operation of the interferometer is described, and the application for measuring the coma aberration of a parabolic mirror used off axis is demonstrated.
24 citations
TL;DR: In this paper, the authors used a reflective grating interferometer to measure the effective focal length of a 1 mm aperture radius diffractive lens, which was obtained by the knowledge of the spatial frequency of two interferometric fringe patterns.
19 citations
ARCO1
TL;DR: In this paper, an interferometric technique based on temperature-dependent optical path length changes in a thin slab of transparent materials, suitable for measuring the thermal coefficient of refractive index, is described.
8 citations
06 Sep 1999
TL;DR: In this paper, an interferometric method for measuring the effective focal length of macroscopic refractive lenses and of a diffractive microlens was proposed, which was performed within the limit of paraxial approximation.
Abstract: We describe an interferometric method for measuring effective focal length of lenses. Measurement of the effective focal lengths of macroscopic refractive lenses and of a diffractive microlens are performed within the limit of paraxial approximation. The technique uses a reflective grating interferometer to produce a fringe pattern with a regular pitch. The lens under test is illuminated by the interference pattern and the focal length is obtained by the knowledge of the spatial frequency in a fixed aperture. Three imags of the interference pattern are stored by using a CCD camera: two of them are imaged by the lens under test placed at two different position, an one is the reference pattern with no lens inserted in the set-up. A 1D fast Fourier algorithm is applied to the digitized image and the phase modulo 2 (pi) is reconstructed. The phase is unwrapped and averaged to calculate the spatial fringe frequency inside the chosen aperture. The method has been applied for measuring the focal length of macroscopic refractive lenses and of a 1mm aperture diffractive microlens.
5 citations
29 Dec 1999
TL;DR: In this article, an automated Fourier transform method of phase retrieval of a carrier-modulated moire fringe pattern is presented, which can provide fast and accurate determination of the phase information by removing the carrier without shifting in frequency domain.
Abstract: An automated Fourier-transform method of phase retrieval of moire interferometric fringe pattern is presented. The method is shown to provide fast and accurate determination of the phase information by removing the carrier without shifting in frequency domain the filtered Fourier spectrum of the carrier-modulated moire fringe pattern. The principle of the method is described and moire interferometric measurements with submicron sensitivity of the in-plane displacement fields of thick carbon fiber/graphite-PEEK composite laminates are analyzed as example of application of the technique.
4 citations
29 Dec 1999
TL;DR: In this article, an interferometric technique based on high precision 2D spatial fringe analysis Fourier method for measuring the elastic constant of nematic liquid crystals is described, since the determination of the elastic anisotropy relies on the measurement of the ratios between the elastic constants.
Abstract: In this paper we describe an interferometric technique based on high precision 2D spatial fringe analysis Fourier method for measuring the elastic constant of nematic liquid crystals. Since the determination of the elastic anisotropy relies on the measurement of the ratios between the elastic constants, this technique provides a powerful and high accuracy method for characterizing nematic liquid crystals.
2 citations
17 Aug 1999
TL;DR: In this paper, an automated Fourier transform method of phase retrieval of a carrier-modulated moire fringe pattern is presented, which is shown to provide fast and accurate determination of the phase information by removing the carrier without shifting in frequency domain.
Abstract: An automated Fourier-transform method of phase retrieval of moire interferometric fringe pattern is presented. The method is shown to provide fast and accurate determination of the phase information by removing the carrier without shifting in frequency domain the filtered Fourier spectrum of the carrier-modulated moire fringe pattern. The principle of the method is described and moire interferometric measurements with submicron sensitivity of the in-plane displacement fields of thick carbon fiber/PEEK composite laminates are analyzed as example of application of the technique.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
2 citations
ARCO1
TL;DR: In this paper, an interferometric technique based on two-dimensional Fourier fringe analysis for measuring the refractive indices and the thermo-optic coefficients of semiconductor-doped glasses suitable for optical waveguide fabrication is presented.
Abstract: We report on an interferometric technique based on two-dimensional Fourier fringe analysis for measuring the refractive indices and the thermo-optic coefficients of semiconductor-doped glasses suitable for optical waveguide fabrication The principle of the measurement method is discussed The thermo-optic coefficients of semiconductor-doped Schott glass filters have been determined in the temperature range 25-85 °C
1 citations
29 Dec 1999
TL;DR: In this article, an interferometric technique based on temperature dependent optical path length changes in thin slab of transparent materials, suitable for measuring the thermo-optic coefficients of the transparent materials is described.
Abstract: We describe an interferometric technique based on temperature dependent optical path length changes in thin slab of transparent materials, suitable for measuring the thermo-optic coefficients of transparent materials. This technique allows an accurate determination of the fringe shift corresponding to a change in the sample temperature, by means of a two fringe pattern Fourier-transform based processing algorithm for phase retrieval. The principle of measurement of the method and its applications to the measurements of the thermo-optic coefficients of some commercial glasses are presented and discussed.
1 citations
17 Aug 1999
TL;DR: In this paper, a fringe projection technique for measuring the index of refraction of transparent liquid materials is presented and discussed, and the authors discuss the application of the fringe projection for detecting adulteration of liquid commonly used and pollution monitoring.
Abstract: Measurement of the refractive index of liquids is of great importance in applications such as characterization and control of adulteration of liquid commonly used and in pollution monitoring We present and discuss a fringe projection technique for measuring the index of refraction of transparent liquid materials© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only