Pietro Ferraro

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.

Capteur optique integre pouvant mesurer les contraintes et la temperature a l'aide d'un seul reseau de diffraction

Abstract: Un capteur optique integre presente une pluralite de couches (10-20), et une fibre optique dotee d'un reseau de fibre (28) et prevue entre les couches (14-16). Les couches (10-20) sont constituees de filaments (22) et de resine (24) presentant des coefficients de dilatation thermique differents, les filaments etant orientes de sorte que des efforts residuels transversaux inegaux agissant a travers la geometrie d'une region riche en resine entourant le reseau (28) dans la fibre (21) soient crees. Les efforts residuels transversaux inegaux provoquent une birefringence dans le reseau (28), lequel reflechit alors de la lumiere (32) a deux longueurs d'onde a separation predeterminee, chacune le long d'un axe de polarisation different. La separation des longueurs d'onde et la longueur d'onde moyenne de chaque cote de ladite separation presentent des sensibilites differentes a la temperature et aux contraintes, ce qui permet une mesure separee de la temperature et des contraintes au moyen d'un seul reseau. La birefringence est maximisee lorsque les filaments (22) des couches adjacentes (10, 12) sont orientes a 90° par rapport a l'axe longitudinal (axe des Z) de la fibre (21).

AI-aided holographic flow cytometry for label-free identification of ovarian cancer cells in the presence of unbalanced datasets

Abstract: Liquid biopsy is a valuable emerging alternative to tissue biopsy with great potential in the noninvasive early diagnostics of cancer. Liquid biopsy based on single cell analysis can be a powerful approach to identify circulating tumor cells (CTCs) in the bloodstream and could provide new opportunities to be implemented in routine screening programs. Since CTCs are very rare, the accurate classification based on high-throughput and highly informative microscopy methods should minimize the false negative rates. Here, we show that holographic flow cytometry is a valuable instrument to obtain quantitative phase-contrast maps as input data for artificial intelligence (AI)-based classifiers. We tackle the problem of discriminating between A2780 ovarian cancer cells and THP1 monocyte cells based on the phase-contrast images obtained in flow cytometry mode. We compare conventional machine learning analysis and deep learning architectures in the non-ideal case of having a dataset with unbalanced populations for the AI training step. The results show the capacity of AI-aided holographic flow cytometry to discriminate between the two cell lines and highlight the important role played by the phase-contrast signature of the cells to guarantee accurate classification.

Photolithography by a tunable electro-optical lithium niobate phase array

Abstract: Photolithography experiments are performed by means of an optical phase mask with electrooptically tunable phase step. The phase mask consists of a 2-dimensional hexagonal lattice of inverted ferroelectric domains fabricated on a z-cut lithium niobate substrate. The electro-optically tunable phase step, between inverted domain, is obtained by the application of an external electric field along the z axis of the crystal via transparent electrodes. The collimated beam of an argon laser passes through the phase mask and the near field intensity patterns, at different planes of the Talbot length and for different values of the applied voltage, are used for photolithographic experiments. Preliminary results are shown and further applications are discussed.

Tomographic phase microscopy of rolling cells in microfluidic flow

Abstract: We propose a tomographic reconstruction method for three-dimensional refractive index mapping of full-rotating cells in a microfluidic channel. Rolling angle recovery is achieved by exploiting the morphometric features of cells.

Biological elements carry out optical tasks in coherent imaging systems

Abstract: We show how biological elements, like live bacteria species and Red Blood Cells (RBCs) can accomplish optical functionalities in DH systems. Turbid media allow coherent microscopy despite the strong light scattering these provoke, acting on light just as moving diffusers. Furthermore, a turbid medium can have positive effects on a coherent imaging system, providing resolution enhancement and mimicking the action of noise decorrelation devices, thus yielding an image quality significantly higher than the quality achievable through a transparent medium in similar recording conditions. Besides, suspended RBCs are demonstrated to behave as controllable liquid micro-lenses, opening new possibilities in biophotonics for endoscopy imaging purposes, as well as telemedicine for point-of-care diagnostics in developing countries and low-resource settings.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

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.

Fiber grating sensors

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.