Author
Pietro Ferraro
Other affiliations: Aeritalia, Centre national de la recherche scientifique, Olivetti ...read more
Bio: Pietro Ferraro is an academic researcher from National Research Council. The author has contributed to research in topics: Digital holography & Holography. The author has an hindex of 61, co-authored 653 publications receiving 12666 citations. Previous affiliations of Pietro Ferraro include Aeritalia & Centre national de la recherche scientifique.
Papers published on a yearly basis
Papers
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TL;DR: Inspired by human walking, a novel magnetic microrobot with two pseudopods was designed in this article, which can subtly lift and move two feet alternately to walk forward.
Abstract: Magnetic microrobots have been developed for various biomedical applications, such as microswimmers for indirect manipulation and assembly of objects. When non-magnetic targets fall or adhere to the substrate by gravity, the indirect manipulation is required to move objects on substrate surface. Inspired by human walking, a novel magnetic microrobot with two pseudopods was designed. Driven by a periodic magnetic field, the structure can subtly lift and move two feet alternately to walk forward. The amplitude and frequency of oscillation were optimized and the controllability of the system was evaluated through performing the motion along planned paths with a velocity of 3.5 mm/s. Finally, microbeads and cell aggregates were pushed and arranged together by the microrobot, which shows potential application in flexible microassembly on substrate surface.
12 citations
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TL;DR: This work reports a voltage-free pyro-electrification (PE) process able to induce a permanent dipole orientation into polymer sheets under both mono- and bipolar distribution and shows the reliability of the technique for different polymers and for different applications ranging from live cell patterning to biofilm formation tests for bacteria linked to food-processing environments.
Abstract: Localized electric fields have become, in recent years, a source of inspiration to researchers and laboratories thanks to a huge amount of applications derived from it, including positioning of microparticles as building blocks for electrical, optical, and magnetic devices. The possibility of producing polymeric materials with surface charge thus opens new perspectives for applications where process simplicity and cost-effectiveness of flexible electronics are of fundamental importance. In particular, the influence of surface charges is widely studied and is a critical issue especially when new materials and functional technologies are introduced. Here, we report a voltage-free pyro-electrification (PE) process able to induce a permanent dipole orientation into polymer sheets under both mono- and bipolar distribution. The technique makes use of the pyroelectric effect for generating electric potentials on the order of kilovolts by an easy-to-accomplish thermal treatment of ferroelectric lithium niobate (LN) crystals. The PE allows us to avoid the expensive and time-consuming fabrication of high-power electrical circuits, as occurs in traditional generator-based techniques. Since the technique is fully compatible with spin-coating-based procedures, the pyro-electrified polymer sheets are easily peeled off the surface of the LN crystal after PE completion, thus providing highly stable and freestanding charged sheets. We show the reliability of the technique for different polymers and for different applications ranging from live cell patterning to biofilm formation tests for bacteria linked to food-processing environments.
11 citations
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TL;DR: In this article, the authors demonstrate that nano-droplets can be drawn from liquid drop or film reservoirs through a sort of milking effect achieved by the absorption of IR laser radiation into a pyroelectric crystal.
Abstract: Liquid handling at micron- and nano-scale is of paramount importance in many fields of application such as biotechnology and biochemistry. In fact, the microfluidics technologies play an important role in lab-on-a-chip devices and, in particular, the dispensing of liquid droplets is a required functionality. Different approaches have been developed for manipulating, dispensing and controlling nano-droplets under a wide variety of configurations. Here we demonstrate that nano-droplets can be drawn from liquid drop or film reservoirs through a sort of milking effect achieved by the absorption of IR laser radiation into a pyroelectric crystal. The generation of the pyroelectric field induced by the IR laser is calculated numerically and a specific experiment has been designed to visualize the electric field stream lines that are responsible for the liquid milking effect. The experiments performed are expected to open a new route for the visualization, measure and characterization procedures in the case of electrohydrodynamic applications.
11 citations
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TL;DR: A training strategy is developed, based on deep and feature based machine learning models, in order to extract complex amplitude information of the sample by skipping the classical reconstruction process for classifying different neuroblastoma cells.
Abstract: The label-free single cell analysis by machine and Deep Learning, in combination with digital holography in transmission microscope configuration, is becoming a powerful framework exploited for phenotyping biological samples. Usually, quantitative phase images of cells are retrieved from the reconstructed complex diffraction patterns and used as inputs of a deep neural network. However, the phase retrieval process can be very time consuming and prone to errors. Here we address the classification of cells by using learning strategies with images coming directly from the raw recorded digital holograms, i.e. without any data processing or refocusing involved. Indeed, in the raw digital hologram the entire complex amplitude information of the sample is intrinsically embedded in the form of modulated fringes. We develop a training strategy, based on deep and feature based machine learning models, in order extract such information by skipping the classical reconstruction process for classifying different neuroblastoma cells. We provided an experimental validation by using the proposed strategy to classify two neuroblastoma cell lines.
11 citations
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02 Aug 2004
TL;DR: In this article, the authors present a method for in-situ visualization of electric field domain reversal in congruent lithium niobate (LN) through an electro-optic interferometric technique.
Abstract: We present a method for in-situ visualization of electric field domain reversal in congruent lithium niobate (LN) through an electro-optic interferometric technique. The crystal refractive index n changes by the linear electro-optic and piezoelectric effects along the z crystal axis, due to the external electric field. This variation depends on the domain orientation so that two adjacent antiparallel domains present a refractive index difference equal to 2Dn which is used for in-situ visualization of the reversed domain pattern during formation. A digital holographic (DH) technique is employed for a two-dimensional (2D) reconstruction of the wavefield transmitted by the sample in amplitude and phase during the process. The corresponding amplitude-map and phase-map movies are presented. The amplitude-map gives qualitative information about the spatial evolution of the domain boundaries while the phase-map provides measurement of the 2D distribution of the phase shift induced along the z axis. The phase-map movies provide unequivocal information about the spatial distribution of the reversed domain regions. This technique can be used as in-situ monitoring method alternative to the measurement of the poling current which provides information only about the amount of charge delivered to the sample, ignoring the spatial distribution of the domain boundaries.
11 citations
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28,685 citations
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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
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TL;DR: In this paper, the authors review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings and intragrating sensing concepts.
Abstract: We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors.
3,665 citations