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.

Micro-optical foundry: 3D lithography by freezing liquid instabilities at nanoscale

Abstract: The pyroelectric functionality of a Lithium Niobate (LN) substrate is used for non-contact manipulation of polymeric material. In this work we introduced a novel approach for fabricating a wide variety of soft solid-like microstructures, thus leading to a new concept in 3D lithography. A relatively easy to accomplish technique has been demonstrated for curing different transient stages of polymer fluids by rapid cross-linking of PDMS. The method is twofold innovative thanks to the electrode-less configuration and to the rapid formation of a wide variety of 3D solid-like structures by exploiting polymer instabilities. This new and unique technique is named "pyro-electrohydrodynamic (PEHD) lithography", meaning the generation of structures by using forces produced by electric fields generated by the pyroelectric effect. The fabrication of polymer wires, needles, pillars, cones, or microspheres is reported, and practical proofs of their use in photonics are presented.

On monocytes and lymphocytes biolens clustering by in flow holographic microscopy

Abstract: Live cells act as biological lenses and can be employed as real‐world optical components in bio‐hybrid systems. Imaging at nanoscale, optical tweezers, lithography and also photonic waveguiding are some of the already proven functionalities, boosted by the advantage that cells are fully biocompatible for intra‐body applications. So far, various cell types have been studied for this purpose, such as red blood cells, bacterial cells, stem cells and yeast cells. White Blood Cells (WBCs) play a very important role in the regulation of the human body activities and are usually monitored for assessing its health. WBCs can be considered bio‐lenses but, to the best of our knowledge, characterization of their optical properties have not been investigated yet. Here, we report for the first time an accurate study of two model classes of WBCs (i.e., monocytes and lymphocytes) by means of a digital holographic microscope coupled with a microfluidic system, assuming WBCs bio‐lens characteristics. Thus, quantitative phase maps for many WBCs have been retrieved in flow‐cytometry (FC) by achieving a significant statistical analysis to prove the enhancement in differentiation among sphere‐like bio‐lenses according to their sizes (i.e., diameter d) exploiting intensity parameters of the modulated light in proximity of the cell optical axis. We show that the measure of the low intensity area (S: Iz

Combining lateral shear interferometry with digital holography for quantitative phase microscopy

Abstract: By combining the concept of Lateral Shear Interferometry (LSI) with Digital Holography we demonstrate that quantitative phase microscopy (QPM) can be used for investigation in different field of applications. The proposed approach gives some important advantages compared to other methods used for QPM. The method is a true single image QPM approach. In fact by using the digital shear of the reconstructed phase map in the image plane the defocus aberration introduced by the microscope objective can efficiently removed. In addition in most cases the unwrapping procedure can be avoided greatly simplifying the phase-map recovery for quantitative measurement. Numerical lateral shear of the reconstructed wave front in the image plane makes it possible to retrieve the derivative of the wave front. In analogy with the standard procedure usually applied in optical testing by means of LSI, the wave front can be reconstructed.

Full 3D morphology of diatoms flowing in a microfluidic channel by digital holographic microscopy

Abstract: In this paper, we present a new approach for three-dimensional reconstruction and biovolume estimation of some species of diatoms. An optofluidic platform, composed by an optical tweezer and holographic modulus, is employed to retrieve several holograms at different angular positions, which are processed by the shape from silhouette algorithm to estimate the 3D shape of the 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.