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.

Ultra-high sensitivity frequency-comb-referenced multi- parametric sensors based on 1-D photonic components

Abstract: A novel generation of sensors of strain, temperature, absolute and relative molecular concentration is reported. Such devices, based on 1-D photonic structures, rely on ultrastable laser sources, referenced to a fiber-based optical frequency comb synthesizer (OFCS). In particular, recent advances in the realization of two complementary laser sensors are presented. One is a spectroscopic facility which exploits frequency mixing in a periodically-poled LiNbO3 crystal to generate highly coherent (a few hundred kHz linewidth) infrared radiation tunable in the 2.9-3.5 micron wavelength range. Such radiation can be coupled to high-finesse enhancement cavities to detect trace amounts of gases, including rare isotopes in natural abundance. The other system, making use of fiber Bragg grating components, provides strain and temperature sensing with extremely high sensitivities (about 100 fe, i.e. 10-13 ΔL/L). Due to the remoteness guaranteed by the fiber coupling, these two systems can both be used in difficult environments and inserted in a multi-parametric network for real-time and continuous monitoring of large areas. Prospects for application in volcanic areas are also discussed.

Capture, processing, and display of real-world 3D objects using digital holography

Abstract: “Digital holography for 3D and 4D real-world objects' capture, processing, and display” (acronym “Real 3D”) is a research project funded under the Information and Communication Technologies theme of the European Commission's Seventh Framework Programme, and brings together nine participants from academia and industry (see www.digitalholography.eu). This three-year project marks the beginning a long-term effort to facilitate the entry of a new technology (digital holography) into the three-dimensional capture and display markets. Its progress at the end of year 2 is summarised.

Combining digital holographic microscopy and optical tweezers: a new route in microfluidic

Abstract: An optical configuration is realized to obtain quantitative phase-contrast maps able to characterize particles floating in a microfluidic chamber by interference microscopy. The novelty is the possibility to drive the sample and measure it thorough the same light path. That is realized by an optical setup made of two light beams coming from the same laser source. One beam provides the optical forces for driving the particle along the desired path and, at same time, it works as object beam in the digital holographic microscope (DHM). The second one acts as reference beam, allowing recording of an interference fringe pattern (i.e., the digital hologram) in an out-of-focus image plane. This work finds application in the field of micromanipulation as, the devise developed allows to operate in microfluidic chambers driving samples flowing in very small volumes. Recently, the field of optical particle micro-manipulation has had rapid growth, due to Optical Tweezers development. A particle is trapped or moved along certain trajectories according to the intensity and phase distribution of the laser beam used. Here, particles freely floating are driven by optical forces along preferential directions and then analyzed by a DHM to numerically calculate their phase-contrast signature. The improvement is that one laser source is employed for making two jobs: driving and analyze the sample. We use two slightly off-axis laser beams coming from a single laser source. The interference between them gives the possibility to record in real-time a sequence of digital holograms, while one of the beam creates the driving force. By this method, a great amount of particles can be analyzed by a real-time recording of DH movies. This allows one to examine each particle at time and characterize it. The optical configuration and the working method are illustrated. Experimental results are shown for polymeric particles and in-vitro.

Strumentazione utilizzante componenti in ottica integrata per la diagnostica di parti con sensori a fibra ottica inclusi o fissati sulla superficie.

Abstract: Strumentazione basata sulla tecnologia dell'ottica integrata per la misura e la diagnostica di parametri fisici su qualsiasi struttura, con l'impiego di sensori ottici a reticolo di Bragg realizzati nel nucleo della fibra ottica e di un dispositivo planare ad ottica integrata per l'analisi del segnale ottico I sensori possono essere fissati alla superficie di una struttura, o inclusi in essa, per consentire la misura di grandezze, quali ad esempio deformazione e temperatura, sia in regime statico sia in regime dinamico L'invenzione puo essere classificata nel campo tecnico della diagnostica e misura di grandezze meccaniche e termiche o nel campo applicativo delle opere civili, nautiche, dei trasporti in generale e delle costruzioni aerospaziali

Holographic processing pipeline for tomographic flow cytometry

Abstract: We report on a smart solution to obtain Tomographic Phase Microscopy (TPM) of samples in microfluidic environment, by exploiting their tumbling while flowing in a microchip. This method permits to observe full 360° of rotating cells, this avoiding the limitation in the accuracy of tomograms, and no mechanical contact neither holographic optical tweezers are needed to rotate the sample. Moreover, it is suitable for application in flowing conditions with high-throughput performances. In fact, it allows to monitor a large number of cells, the only limit being the frame rate of the camera used to acquire data, and to analyze in principle each single cell with high resolution, regardless of its shape or symmetry. This would allow real microfluidic biomedical applications on a large scale. Summarizing, the whole process is accomplished following the subsequent steps: (i) holograms acquisition of cells flowing in microfluidic channels; (ii) 3D tracking and realignment by using either biolens effect or particular symmetries (depending on the object’s structure); (iii) connection between rotation angles and phase maps; (iv) complete 3D image retrieving, displaying the inner structure of the object (i.e. tomography).

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.