Fabrice R A Onofri

Fabrice R A Onofri
French National Centre for Scientific Research | CNRS · Institute for Engineering and Systems Sciences (INSIS)

PhD & Habilitation
Optical and electromagnetic characterization and properties of particle systems (aerosol, colloid, plasma, spray...)

About

268
Publications
27,511
Reads
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1,641
Citations
Introduction
Generally speaking, I'm working on direct and inverse light-scattering problems related to the optical/electromagnetic properties and characterization of nano and micro-particles encountered in various fields (e.g. aerosols, colloids, multiphase flows, dusty plasmas & fusion plasmas,...)
Additional affiliations
October 2007 - present
French National Centre for Scientific Research
Position
  • Director of Research at CNRS
September 2003 - present
CNRS/AFVL Summer school
Position
  • Light scattering by particles & Optical characterization of particle systems
October 1997 - present
Aix-Marseille University
Position
  • Optical diagnostics of fluids and multiphase flows
Education
October 1996 - June 2005
Aix-Marseille Université
Field of study
  • Physics
November 1992 - November 1995
Université de Rouen
Field of study
  • Physics
September 1986 - June 1992
Université de Rouen
Field of study
  • Physics

Publications

Publications (268)
Article
Full-text available
A numerically effective approach was developed for the modeling of spray-drying of colloidal suspensions. This approach was based on the integration of two models. The first is a phenomenological and radially symmetric model accounting for the drying of single-droplets, while the second employs computational fluid dynamics (CFD) simulations to acco...
Article
Full-text available
The image of the photonic jet (also called caustic) formed by a large, transparent, and spherical particle, reconstructed by digital in-line holography, is shown to be similar to the Airy pattern observed at the focus of a diffraction-limited lens. The analysis of this image, real or virtual depending on whether the particle relative refractive ind...
Preprint
The analysis of nano-and microparticle suspensions with micro systems affords improved space-time yields, selectivity, reaction residence times and conversions capabilities. These capabilities are of primary importance in various fields of research and industry. The few microfluidic lab-on-a-chip approaches that have been developed are essentially...
Article
Full-text available
The analysis of nano- and microparticle suspensions with micro systems affords improved space–time yields, selectivity, reaction residence times and conversions capabilities. These capabilities are of primary importance in various fields of research and industry. The few microfluidic lab-on-a-chip approaches that have been developed are essentially...
Preprint
Full-text available
The scattering patterns near the primary rainbow of oblate drops are simulated by extending the vectorial complex ray model (VCRM) [1] to three-dimensional (3D) calculations. With the curvature of wavefront as intrinsic property of a ray, this advanced ray model permits, in principle, to predict the amplitudes and phases of all emergent rays with a...
Article
Full-text available
The scattering patterns near the primary rainbow of oblate drops are simulated by extending the vectorial complex ray model (VCRM) [Opt. Lett. 36, 370 (2011)] to threedimensional (3D) calculations. With the curvature of a wavefront as an intrinsic property of a ray, this advanced ray model permits, in principle, to predict the amplitudes and phases...
Article
Full-text available
This special issue contains a collection of research papers initially intended to be presented in 2020 at the international conference series on “Laser-light and Interactions with Particles (LIP)” which was postponed, due to the Covid pandemic. Conference or not, the pandemic has not stopped Science. We think that this special issue will help to p...
Article
Full-text available
The present preface for the “no-shown” (i.e. covid pandemic) International Laser-light and interactions with particles conference - 2020 (LIP2020) compiles and reviews 23 peer-reviewed papers, providing a significant sample of the issues usually discussed during LIP-conferences.Authors and readers are kindly asked to forgive the authors of the pres...
Code
This windows-based software allows generating fractal aggregates of spherical particles. It uses a Diffusion Limited Aggregation (DLA) algorithm and the so-called fractal equation. The latter is respected, with a prescribed accuracy, at each aggregation step and for a given set of tunable parameters. The software outputs may be used for light scatt...
Conference Paper
Physical insights are provided on the relative contributions of the scattering processes (pure diffraction, specular reflection, tunneling and grazing waves, single refraction…) in the reconstruction of the photonic jet of spherical particles with Digital-in-Line Holography.
Article
Previous JQSRT special issues devoted to the “Laser-light and Interactions with Particles (LIP)” conferences were accompanied by prefaces written for issues published in a single volume, followed by peer-reviewer papers based on the topics discussed during the conferences, see Gouesbet and Brunel (2013) [1] in [2], Gouesbet and Onofri (2015) [3] in...
Conference Paper
Full-text available
L’holographie numérique en ligne est une technique d’imagerie volumétrique particulièrement adaptée à la caractérisation des écoulements dilués qui permet de mesurer simultanément la position dans l’espace, le déplacement, la forme et la taille de particules au sein des ces derniers (bulles, gouttes, etc.). Dans de nombreux domaines, qu’ils concern...
Poster
Full-text available
La diffusion de gouttes non-sphériques en lévitation acoustique est étudiée en comparant diagrammes expérimentaux et numériques. Il ressort de ces travaux que sans modèle de diffusion adéquat un changement quasi imperceptible de leur morphologie peut grandement affecter notre capacité à estimer avec précision leur taille et leur température. Avec u...
Poster
Full-text available
Cette communication expose les principales caractéristiques d’un banc de diffusion multi angulaire dont les aspects novateurs et la pertinence sont testés par le suivi de la dynamique de déstabilisation d’une suspension de silice. Outre la correction de divers biais optiques, ce banc intègre des algorithmes d’inversion couplant modèles d’agrégation...
Poster
Full-text available
Cette communication s’inscrit dans le cadre des recherches sur les procédés d’extraction liquide-liquide utilisés pour le retraitement du combustible nucléaire. Le besoin d’améliorer les capacités et de réduire le coût de développement de la nouvelle génération de colonnes d’extraction impose le déploiement d’outils de simulation dûment validés. Da...
Conference Paper
Full-text available
Cette communication s’inscrit dans le cadre des recherches sur les procédés d’extraction liquide-liquide utilisés pour le retraitement du combustible nucléaire. Le besoin d’améliorer les capacités et de réduire le coût de développement de la nouvelle génération de colonnes d’extraction impose le déploiement d’outils de simulation dûment validés. Da...
Conference Paper
Full-text available
L'influence de la non-sphéricité des gouttes sur leurs diagrammes de diffusion est étudiée avec une approximation d'optique géométrique avancée et des expériences réalisées sous lévitation acoustique. Il ressort de ce ces travaux qu'un changement quasi imperceptible de la morphologie des gouttes peut affecter significativement leurs propriétés de d...
Conference Paper
Full-text available
Cette communication expose les principales caractéristiques d'un banc de diffusion multi angulaire dont les aspects novateurs et la pertinence sont testés par le suivi de la dynamique de déstabilisation d'une suspension de silice. Outre la correction de divers biais optiques, ce banc intègre des algorithmes d'inversion couplant modèles d'agrégation...
Data
The influence of droplet non-sphericity on their rainbow angle scattering patterns is investigated with the Vectorial Complex Ray Model (VCRM) and experiments carried under acoustic levitation. It is shown that quasi-imperceptible change in the morphology of droplets can significantly affect the resolution achievable on the determination of their s...
Conference Paper
Full-text available
The authors have shown recently [1, 2] that digital in-line holography (DIH) can recover some features of the electromagnetic near field of large spherical transparent particles. Among these features, a special attention was paid to the photonic jet whose intensity maxima positioning allows to estimate the particle refractive index. In the present...
Conference Paper
Full-text available
This communication deals with the optical characterization of droplets and fluids parameters that are relevant for liquid-liquid extraction processes, and notably, for nuclear fuel reprocessing. In immiscible liquid–liquid dispersions, i.e. droplets with a homogeneous but low value relative refractive index, the first order rainbow is localized in...
Poster
Full-text available
The influence of droplet non-sphericity on their rainbow angle scattering patterns is investigated with the Vectorial Complex Ray Model (VCRM) and experiments carried under acoustic levitation. It is shown that quasi-imperceptible change in the morphology of droplets can significantly affect the resolution achievable on the determination of their s...
Chapter
Full-text available
This review highlights the various electromagnetic methods, geometrical and physical optics approximations developed so far in the literature to predict the light scattering properties of large bubbles in an optically dilute regime. The underlying problematic is essentially linked to the characterization of bubbly flows or, more generally, multipha...
Article
The capabilities and resolution of the rainbow technique were extended to estimate the size distribution and composition of droplets in liquid–liquid systems. For these droplets, essentially characterized by a low relative refractive index (𝑚≈1.001–1.20), the first-order rainbow is localized in the near-forward to sideways region. It exhibits an un...
Conference Paper
Optical methods for investigating multiphase flows are reviewed and discussed in the scope of the development of apparatus convenient for nuclear fuel reprocessing. Indeed, the various processes implemented (e.g. leaching, solvent extraction, filtration, crystallization, etc.) involve either liquid/gas, liquid/liquid and/or liquid/solid flows. Besi...
Conference Paper
Full-text available
Optical methods for investigating multiphase flows are reviewed and discussed in the scope of the development of apparatus convenient for nuclear fuel reprocessing. Indeed, the various processes implemented (e.g. leaching, solvent extraction, filtration, crystallization, etc.) involve either liquid/gas, liquid/liquid and/or liquid/solid flows. Besi...
Article
G. Gouesbet and F. Onofri Laser-light and Interactions with Particles (LIP), 2016 Journal of Quantitative Spectroscopy & Radiative Transfer 195 (2017) 1–7 http://dx.doi.org/10.1016/j.jqsrt.2017.01.017 This is the preface to a JQSRT special issue devoted to the “Laser-light and Interactions with Particles (LIP)” conference which took place in Xidia...
Conference Paper
Full-text available
Digital in-line holography (DH) is widely used to characterize two-phase flows as it allows determining , simultaneously and in one shot, the shape, 3D center position and size of particles. In this communication, two extensions of DH are presented. The first one concerns particles characterization in astigmatic optical systems (e.g. optical lenses...
Presentation
Full-text available
The capabilities and resolution of the rainbow technique were extended to estimate the size distribution and composition of droplets in homogeneous and hetteregeneous liquid–liquid systems.
Presentation
Full-text available
We report the first experimental validation of the Vectorial Complex Ray Model (VCRM) using the scattering patterns of large oblate droplets trapped in an acoustic field. The two principal radii and refractive index of the droplets are retrieved with a minimization method that involves VCRM predictions and experimental light scattering patterns. Th...
Presentation
Full-text available
Digital in-line holography (DH) is widely used to characterize two-phase flows as it allows de-termining, simultaneously and in one shot, the shape, 3D center position and size of particles. In this communication, two extensions of DH are presented. The first one concerns particles charac-terization in astigmatic optical systems (e.g. optical lense...
Conference Paper
Full-text available
An extension of digital in-line holography to particle and particle systems characterization in complex, i.e. astigmatic, propagation media is presented. To simulate and back propagate holograms in such systems, it is shown that generalized propagators and proper sampling conditions can be derived from the generalized diffraction integral defined i...
Article
Full-text available
A new and computationally efficient approach is proposed for determining the refractive index of spherical and transparent particles, in addition to their size and 3D position, using digital in-line holography. The method is based on the localization of the maximum intensity position of the photonic jet with respect to the particle center retrieved...
Article
Ge-imogolite nanotubes (Al2GeO7H4) can be readily obtained in various lengths, chemical compositions and crystallinities, opening up new perspectives for applications. Their classical synthesis includes the nucleation of roof-tile shaped precursors at room temperature followed by a heat promoted growth (typically 95 °C) for at least 4 to 7 days. To...
Conference Paper
Full-text available
Une « Transformée d'Huygens-Fresnel Généralisée» (THFG) est introduite afin de prendre en compte l'astigmatisme induit par des éléments optiques dans le cadre de la théorie de la diffraction scalaire et de l'optique paraxiale [1]. La THFG, avec une réponse impulsionnelle et des conditions d'échantillonnage idoines, permet une implémentation rigoure...
Conference Paper
Full-text available
La transformée de Fresnel généralisée est étendue afin de prendre en compte l'astigmatisme induit par des éléments optiques en holographie numérique en ligne. Une réponse impulsionnelle et une fonction de transfert généralisées, ainsi que des conditions d'échantillonnage ad hoc, permettent une implémentation rigoureuse de cette transformation. Il e...
Article
In this article, a detailed introduction of the light extinction spectrometry (LES) diagnostics is given. LES allows the direct in situ measurement of the particle size distribution and absolute concentration of dust clouds levitating in plasmas. Using a relatively simple and compact experimental set-up, the dust cloud parameters can be recovered w...
Presentation
Full-text available
Various geometrical and physical effects regarding the scattering of large bubbles are revisited to develop an extended GPOA. Basically, in all developed models the GOA introduced by Van de Hulst is used to describe the scattering patterns outside the singular regions. This model, when properly implemented, provides surprisingly accurate results wh...
Data
Full-text available
The dynamics of a growing tungsten (W) nanoparticle (NP) cloud in a direct-current sputtering discharge were investigated with in-situ Light Extinction Spectroscopy (LES) and laser tomography techniques, as well as off-line electron microscopy and Raman spectroscopy techniques. This experimental work revealed the growth of a first generation of par...
Data
This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...
Data
Full-text available
The dynamics of a growing tungsten (W) nanoparticle (NP) cloud in a direct‐current sputtering discharge were investigated with in‐situ Light Extinction Spectroscopy (LES) and laser tomography techniques, as well as off‐line electron microscopy and Raman spectroscopy techniques. This experimental work revealed the growth of a first generation...
Data
Full-text available
This talk summerizes the work done on the analyzes of the various phenomena that need to be accounted for in modeling the light-scattering properties of large spherical bubbles in the context of geometrical and physical optics approximations. Among these phenomena are interference occurring between higher-order rays, the Goos–Hänchen shift, the tun...
Conference Paper
Full-text available
Several processes used in nuclear research and industry are based on liquid-liquid extraction. This method is designed for selective separation of products in a mixture. As the transfer occurs at the contact surface between both phases, the characterization of the dispersed phase of the emulsion (size distribution of droplets, shape, etc.) is funda...
Poster
Full-text available
this study proposes a better understanding of the growth, the agglomeration phases and the spatial dynamics of a tungsten nanoparticle cloud created in direct-current argon glow sputtering discharge.
Conference Paper
Full-text available
This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...
Conference Paper
Full-text available
This paper considers various phenomena in modeling the light-scattering properties of bubbles in the context of geometrical and physical optics approximations (GOA & POA), opening up perspectives for the computationally efficient prediction of the optical properties of complex shaped bubbles as well as bubbly flows characterization.
Conference Paper
Full-text available
This paper reports investigations on the experimental characterization of large prolate droplets from the analysis of their light scattering patterns in the first rainbow angle region. Inversions, performed with an advanced vectorial complex ray model, clearly demonstrate the necessity to account for extremely small ellipticities.
Poster
Full-text available
This paper reports the work in progress to develop a multi-angle light scattering apparatus allowing routine characterization of liquid suspensions, of nanometer-sized particle and their aggregates, in freely exchangeable sample cells. The specificities of the proposed system consist in three points: the ellipticity of the illuminating beam, a dete...
Article
The growth and the dynamics of a tungsten nanoparticle cloud were investigated in a direct-current low pressure argon glow discharge. Real-time analyses of the dust particle size and number concentration were performed in-situ by light extinction spectrometry, while spatial dynamics of the cloud was investigated with the laser light-sheet scatterin...
Conference Paper
This study details the characterization of two phase flows using digital holography in astigmatic systems through a generalized convolution method derived from the Collins formula.
Article
Full-text available
In this article, a detailed introduction of the light extinction spectrometry (LES)diagnostics is given. LES allows the directin situmeasurement of the particle sizedistribution and absolute concentration of dust clouds levitating in plasmas. Usinga relatively simple and compact experimental set-up, the dust cloud parameters canbe recovered with a...
Article
Full-text available
Organic Photo Sensor (OPS) technology allows printing on conformable plastic-like substrates complex-shaped, arbitrarily-sized and pre-aligned photosensitive elements. This article reports, to the best of our knowledge, the first investigation to implement this emerging technology for Multi-Angle Light Scattering (MALS) characterization of nano- an...
Conference Paper
Full-text available
A review of a recent contributions in the modeling and the optical characterization of droplets, bubbles and nanoparticles.
Data
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Data
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