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.

Spiral formation at microscale by μ-pyro-electrospinning

Abstract: Spiral shapes occur frequently in nature, such as in case of snail shells or in case of the so-called cochlea, namely the auditory portion of the inner ear. They also inspire many technological devices that take advantage of this geometry. Here we show that μ-pyro electrospinning is able to control the whipping instabilities in order to form polymeric spirals directly onto the target support and with true regularity at microscale. The results show that the polymer concentration plays a key role in producing reliable and long spirals. We investigate the cell response to these spiral templates that, thanks to their true regularity, would be useful for developing innovative cochlea regeneration scaffolds.

Holographic display of synthetic 3D dynamic scene

Abstract: A synthetic scene of real-word objects is obtained through the multiplexing of several digital holograms. Moreover, by an opportune numerical hologram deformation, it is possible to synthesize 3D dynamic scenes that can be displayed by means of a spatial light modulator. In fact, the spatial adaptive deformation of digital holograms allows the control of the object position and size in a 3D volume with a high depth of focus. Through this novel technique a 3D dynamic scenes can be projected as an alternative to difficult and heavy computations needed to generate realistic-looking computer generated holograms. Finally we report the result of a pilot experiment to evaluate how viewers perceive depth in a conventional single-view display of these dynamic 3D scenes.

Investigation on Axicon Transformation in Digital Holography for Extending the Depth of Focus in Bio-Microfluidics Applications

Abstract: Limited depth of focus (DOF) is one main shortage in traditional optical microscopy systems that severely affect simultaneous visualization of objects at different depths in the same field of view. In this paper, we propose a novel method to enhance the DOF in digital holography that consists of applying a numerical axicon transformation to the hologram during the reconstruction process. The idea behind this is to exploit the well-known ability of an axicon lens to create long and narrow focal lines along the optical axis. By this approach, we demonstrate that it is possible to obtain an extended focused image in which objects located at different depths are simultaneously visualized in good focus. First, the proposed method is tested in a case study of three different wires, positioned on different planes and recorded in lensless configuration. A comparison with a common DOF extension approach based on cubic phase function is performed. Finally, experiments of motile cells, flowing in a microfluidic channel and at different depths, are investigated for demonstrating the effectiveness of the proposed approach in bio-microfluidics.

3D imaging lipidometry in single cell by in-flow holographic tomography

Abstract: The most recent discoveries in the biochemical field are highlighting the increasingly important role of lipid droplets (LDs) in several regulatory mechanisms in living cells. LDs are dynamic organelles and therefore their complete characterization in terms of number, size, spatial positioning and relative distribution in the cell volume can shed light on the roles played by LDs. Until now, fluorescence microscopy and transmission electron microscopy are assessed as the gold standard methods for identifying LDs due to their high sensitivity and specificity. However, such methods generally only provide 2D assays and partial measurements. Furthermore, both can be destructive and with low productivity, thus limiting analysis of large cell numbers in a sample. Here we demonstrate for the first time the capability of 3D visualization and the full LD characterization in high-throughput with a tomographic phase-contrast flow-cytometer, by using ovarian cancer cells and monocyte cell lines as models. A strategy for retrieving significant parameters on spatial correlations and LD 3D positioning inside each cell volume is reported. The information gathered by this new method could allow more in depth understanding and lead to new discoveries on how LDs are correlated to cellular functions. 3D D. Pirone, P. Memmolo, V. Bianco, L. Iom- marini and P. Ferraro analyzed and discussed the tomographic reconstruc-tions and data. I. Kurelac, S. Lemma and L. Iommarini performed FM ex- periments and data analysis; G. Pasquinelli and S. Valente performed the TEM; all the authors contributed to critical discussion of the results and contributed to write the manuscript. P. Ferraro supervised the research.

Detection and visualization improvement of Spermatozoa cells by Digital Holography

Abstract: Numerical analysis is implemented to investigate biological sample starting from Digital Holographic (DH) recording. The aim is to improve visualization and detection of cow spermatozoa. Digital holograms are recorded in the off-axis geometry where optical setup is a Mach-Zehnder interferometer. Then holograms are numerically manipulated to retrieve, besides the usual Quantitative Phase Map (QPM), Differential Interference Contrast (DIC) visualization. Furthermore, a new approach , named digital self-referencing holography, is described it’s able to accomplish quantitative phase analysis especially useful for specimen flowing in microfluidic channels.

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.