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.

Evaluation of rigid rotations in flexural loading tests by holographic interferometry

Abstract: The authors develop a simple method based on holographic interferometry for determining the Poisson's ratio and the Young's modulus for a specimen subjected to four-point flexural testing that evaluates and eliminates the effects of the unwanted rigid-body rotations. In the experimental setup, they use an additional mirror to record the underside and the front surface of the specimen simultaneously. The theoretical analysis shows that it is possible to correlate the holographic fringe pattern of the underside and front surface of the sample. Each rotation angle can be evaluated by counting the fringe orders between two points chosen on the two fringe patterns.

Advanced label-free cellular identification in flow by collaborative coherent imaging techniques

Abstract: We investigated subclasses of living peripheral blood cells in a microfluidic-based system, with the aim to characterize their morphometric and optical properties, and to track their position in flow in a label-free modality. We employed two coherent imaging techniques: a scattering approach of precisely aligned single cells, and a digital holography approach to achieve optical cell reconstructions in flow. Cells were first 3D-aligned in round shaped capillary and subsequently measured in a following square shaped channel. Results were obtained at two fixed measurement positions, the first one was chosen close to the entrance of the measurement channel to ensure 3D cell alignment for scattering investigations; the second was placed 15 mm after to study additional cell properties by digital holography and to investigate possible variations of axial cell positions. First, the refractive index, ratio of the nucleus over cytoplasm, and cell dimension were investigated from scattering investigations. Further quantitative phase-contrast reconstructions by digital holography were employed to calculate surface area, dry mass, biovolume and positions of cells using the scattering outcomes as input parameters. The precise cell alignment at the first measurement position could be confirmed. At the second measurement position a full label-free characterization of cell classes in distinct vertical positions was realized and supported by applied microfluidic force calculations, which can be used to align, deform and/or separate cells. Our results confirm the possibility to differentiate cell classes in flow, thus avoiding chemical cell staining or labeling, which are nowadays used.

Detection of Survivors in Fire Scenes by Mid-IR Digital Holography

Abstract: We developed two different systems for real-time imaging live humans through smoke and flames. The capabilities of both the devices are discussed showing the possibility to employ them in case of real fire accidents.

Microfluidic engineering for continuous in-flow cyto-tomography

Abstract: The possibility to investigate cells in microfluidic flow by using a full 3D morphometry analysis is highly demanded to achieve information about their healthiness. Recently, the tomographic flow cytometry by digital holography has been demonstrated to monitor red blood cells in microfluidics environment by simply applying flux pressure to induce random self-rotation of flowing cells. Here, we provide a microfluidic solution to engineer the flow with the aim to ensure the full 360 degree of angle rotation of all cells in the field of view. We test the proposed methods for circulating tumour cells.

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.