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Author

Giovanni Pierattini

Other affiliations: Olivetti
Bio: Giovanni Pierattini is an academic researcher from ARCO. The author has contributed to research in topics: Digital holography & Holography. The author has an hindex of 25, co-authored 128 publications receiving 3222 citations. Previous affiliations of Giovanni Pierattini include Olivetti.


Papers
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Journal ArticleDOI
TL;DR: In this article, the temporal behavior of the concentration grating versus the sample properties and its effect on the detected diffracted beam was studied. Explicit expressions for the output intensity taking into account both the generated amplitude and phase gratings were given for the generated intensity taking the generated phase and amplitude grating into account.
Abstract: In forced Rayleigh scattering of mixtures or suspensions the temperature gratings generate, by the Soret effect, concentration gratings that may be very important since they produce both a phase and an amplitude grating superimposed on the principal one. The experimental evidence of their influence was given by Thyagarajan and Lallemand using a mixture of carbondisulfide and ethanol. In this paper we study the temporal behaviour of the concentration grating versus the sample properties and its effect on the detected diffracted beam. Explicit expressions are given for the output intensity taking into account both the generated amplitude and phase gratings.

20 citations

Journal ArticleDOI
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

Journal ArticleDOI
M. de Angelis1, S. De Nicola1, Pietro Ferraro1, Andrea Finizio1, Giovanni Pierattini1 
TL;DR: In this article, a simple and compact interferometric system, which makes use of a reflective-type diffraction grating, has been developed for measuring the refractive index of liquids.
Abstract: A simple and compact interferometric system, which makes use of a reflective-type diffraction grating, has been developed for measuring the refractive index of liquids. This paper describes the details of the system, which is easy to align and compact, and a series of measurements performed on liquids. An analysis of the accuracy of the method is presented, which is proven to be within one part in .

19 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a digital holographic microscope (DHM) to carry out a noncontact and non-destructive characterization of a microheater integrated on a silicon nitride membrane and subjected to a high thermal load.
Abstract: This paper describes the possibility of employing a digital holographic microscope (DHM) to carry out a noncontact and nondestructive characterization of a microheater integrated on a silicon nitride membrane and subjected to a high thermal load. Microheaters can be affected by the presence of the residual stress due to the technological processes appearing in the form of undesired bowing of the membrane. Moreover, when the temperature of the microheater increases, a further warpage of the structure can be induced. A DHM allows for evaluation, with high accuracy, the deformations due to the residual stress and how these deformations are affected by the thermal loads due to the microheater operating mode. In particular, this dynamic analysis is made possible by measuring the unwanted longitudinal displacement induced by the thermal expansion of both the device and its mechanical support. Taking into account this displacement, it is possible to have a continuous monitoring of profile deformation induced by the working condition of the microheater.

19 citations

Patent
23 Feb 2006
TL;DR: In this paper, the authors proposed a holographic method with numerical reconstruction for obtaining an image of a three-dimensional object, employing a digitalised hologram of an object, and comprising a step A. wherein, starting from the digitalized hologram, extracting a phase image of said object corresponding to a bidimensional matrix MD of distance values; a step B. wherein a monodimensional subassembly SD of the distance value assembly present in matrix MD is selected, subassembling SD containing distance values dk, and a step C. wherein for each distance value dk
Abstract: The invention concerns a holographic method with numerical reconstruction for obtaining an image of a three-dimensional object, said method employing a digitalised hologram of an object, and comprising a step A. wherein, starting from the digitalised hologram, extracting a phase image of said object corresponding to a bidimensional matrix MD of distance values; a step B. wherein a monodimensional subassembly SD of the distance value assembly present in matrix MD of the method step A is selected, subassembly SD containing distance values dk; a step C. wherein for each distance value dk, extracting from matrix MD a iso-level assembly IQdk corresponding to a monodimensional assembly of bidimensional coordinates of said object,- a step D. wherein for each distance value dk, reconstructing, starting from the digitalised hologram, a bidimensional matrix IMdk of intensity values relevant to said object; a step E. wherein, from each bidimensional matrix IMdk a bidimensional matrix IFdk of intensity values is extracted corresponding to the bidimensional coordinates of the iso-level assembly IQdk; a step F. wherein, starting from intensity values IFdk from the bidimensional coordinates of the iso-level assembly IQdk and from the relevant distance values dk, reconstructing the three-dimensional intensity image of said object, and wherein the resolution of the bidimensional matrix IMdk for all values of k is identical to the resolution of matrix MD of distance values.

19 citations


Cited by
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Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

Journal ArticleDOI
TL;DR: In this article, the physical mechanisms and the main experimental parameters involved in femtosecond laser micromachining of transparent materials, and important emerging applications of the technology are described.
Abstract: Femtosecond laser micromachining can be used either to remove materials or to change a material's properties, and can be applied to both absorptive and transparent substances. Over the past decade, this technique has been used in a broad range of applications, from waveguide fabrication to cell ablation. This review describes the physical mechanisms and the main experimental parameters involved in the femtosecond laser micromachining of transparent materials, and important emerging applications of the technology. Interactions between laser and matter are fascinating and have found a wide range of applications. This article gives an overview of the fundamental physical mechanisms in the processing of transparent materials using ultrafast lasers, as well as important emerging applications of the technology.

2,533 citations

Journal ArticleDOI
TL;DR: The principles and major applications of digital recording and numerical reconstruction of holograms (digital holography) are described, which are applied to measure shape and surface deformation of opaque bodies and refractive index fields within transparent media.
Abstract: This article describes the principles and major applications of digital recording and numerical reconstruction of holograms (digital holography). Digital holography became feasible since charged coupled devices (CCDs) with suitable numbers and sizes of pixels and computers with sufficient speed became available. The Fresnel or Fourier holograms are recorded directly by the CCD and stored digitally. No film material involving wet-chemical or other processing is necessary. The reconstruction of the wavefield, which is done optically by illumination of a hologram, is performed by numerical methods. The numerical reconstruction process is based on the Fresnel–Kirchhoff integral, which describes the diffraction of the reconstructing wave at the micro-structure of the hologram. In the numerical reconstruction process not only the intensity, but also the phase distribution of the stored wavefield can be computed from the digital hologram. This offers new possibilities for a variety of applications. Digital holography is applied to measure shape and surface deformation of opaque bodies and refractive index fields within transparent media. Further applications are imaging and microscopy, where it is advantageous to refocus the area under investigation by numerical methods.

1,171 citations

Journal ArticleDOI
TL;DR: This paper presents a meta-analyses of Fourier-Transform Profilometry and its applications in 3-D Shape Measurement and Surface Profile Measurement for Structured Light Pattern and 4-Core Optical-Fiber.

1,110 citations

Journal ArticleDOI
TL;DR: Digital holography is an emerging field of new paradigm in general imaging applications as discussed by the authors, and a review of a subset of the research and development activities in digital holographic microscopy techniques and applications is presented.
Abstract: Digital holography is an emerging field of new paradigm in general imaging applications. We present a review of a subset of the research and development activities in digital holography, with emphasis on microscopy techniques and applications. First, the basic results from the general theory of holography, based on the scalar diffraction theory, are summarized, and a general description of the digital holographic microscopy process is given, including quantitative phase microscopy. Several numerical diffraction methods are described and compared, and a number of representative configurations used in digital holography are described, including off-axis Fresnel, Fourier, image plane, in-line, Gabor, and phase-shifting digital holographies. Then we survey numerical techniques that give rise to unique capabilities of digital holography, including suppression of dc and twin image terms, pixel resolution control, optical phase unwrapping, aberration compensation, and others. A survey is also given of representative application areas, including biomedical microscopy, particle field holography, micrometrology, and holographic tomography, as well as some of the special techniques, such as holography of total internal reflection, optical scanning holography, digital interference holography, and heterodyne holography. The review is intended for students and new researchers interested in developing new techniques and exploring new applications of digital holography.

672 citations