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Giorgio Margaritondo

Cette personne a quitté l’EPFL

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Publications associées (132)

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Hard x-ray Zernike microscopy reaches 30 nm resolution

Giorgio Margaritondo, Vincent Gajdosik

Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microsc ...

Optical Society of America2011

A simplified description of X-ray free-electron lasers

Giorgio Margaritondo, Primoz Rebernik Ribic

It is shown that an elementary semi-quantitative approach explains essential features of the X-ray free-electron laser mechanism, in particular those of the gain and saturation lengths. Using mathematical methods and derivations simpler than complete theor ...

International Union of Crystallography2011

Fabrication of single crystal CuGaS2 nanorods by X-ray irradiation

Giorgio Margaritondo

CuGaS2 nanorods were synthesized by irradiating the precursor solution with intense X-rays. The products are single crystal nanorods with preferential [220] growth and a uniform size distribution. We also report on the photoresponse of drop-cast films of t ...

Royal Society of Chemistry2011

Gold nanoparticles: BSA (Bovine Serum Albumin) coating and X-ray irradiation produce variable-spectrum photoluminescence

Giorgio Margaritondo

We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emi ...

Elsevier Science Sa2015

Photoelectron spectromicroscopy and spectronanoscopy at synchrotrons: Growing impact on life sciences and materials science

Giorgio Margaritondo

We review the historical and recent development of experimental techniques that are based on the combination of photoemission spectroscopy and high lateral resolution. The discussion specifically deals with the essential features of the two main classes of ...

Elsevier2010

Dynamical growth behavior of copper clusters during electrodeposition

Giorgio Margaritondo

Ultrahigh resolution full-field transmission x-ray microscopy enabled us to observe detailed phenomena during the potentiostatic copper electrodeposition on polycrystalline gold. We detected two coexisting cluster populations with different sizes. Their gr ...

American Institute of Physics2010

Phase contrast radiography of Lewy bodies in Parkinson disease

Giorgio Margaritondo

Parkinson's disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons and the presence of Lewy bodies in neurons. Morphological study of Lewy bodies is important to identify the causes and the processes of ...

Elsevier2006

The new X-ray/visible microscopy MAXWELL technique for fast three-dimensional nanoimaging with isotropic resolution

Giorgio Margaritondo, Lin Yang

Microscopy by Achromatic X-rays With Emission of Laminar Light (MAXWELL) is a new X-ray/visible technique with attractive characteristics including isotropic resolution in all directions, large-volume imaging and high throughput. An ultrathin, laminar X-ra ...

Nature Portfolio2022

Imaging with Coherent X-rays: From the Early Synchrotron Tests to SYNAPSE

Giorgio Margaritondo

The high longitudinal and lateral coherence of synchrotron X-rays sources radically transformed radiography. Before them, the image contrast was almost only based on absorption. Coherent synchrotron sources transformed radiography into a multi-faceted tool ...

MDPI2021

Optimizing the size and surface properties of polyethylene glycol (PEG)-gold nanoparticles by intense x-ray irradiation

Giorgio Margaritondo

The polyethylene glycol (PEG) modified gold nanoparticle complex was synthesized by a one-solution synchrotron x-ray irradiation method. The impact on the structure and morphology of the gold nanoparticles of process parameters such as the PEG molecular we ...

2008

Photobleaching-free infrared near-field microscopy localizes molecules in neurons

Giorgio Margaritondo, Kai Johnsson, Harald Hirling, Johanna Generosi

High-resolution detection of specific molecules in cells is a major challenge in biology. We show that infrared scanning near-field microscopy can detect the spatial distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid–type glutamate r ...

2008

Simple dose rate measurements for a very high synchrotron X-ray flux

Giorgio Margaritondo

Dose measurements based on methylene blue (MB) bleaching, widely used for ultraviolet light, can also be applied to X-rays including very high flux levels. This method has been tested by using both MB bleaching and Fricke dosimetry for a conventional monoc ...

International Union of Crystallography2009

Who were the founders of synchrotron radiation? Historical facts and misconceptions

Giorgio Margaritondo

Synchrotron radiation is now a gigantic worldwide enterprise involving tens of thousands of researchers. Quite famous in this field are the landmark accomplishments of illuminated pioneers like Dave Shirley. Somewhat less known, however, are the historical ...

A V S AMER INST PHYSICS2022

Full-field hard x-ray microscopy below 30 nm: a challenging nanofabrication achievement

Giorgio Margaritondo

The fabrication of devices to focus hard x-rays is one of the most difficult-and important-challenges in nanotechnology. Here we show that Fresnel zone plates combining 30 nm external zones and a high aspect ratio finally bring hard x-ray microscopy beyond ...

Institute of Physics2008

Imaging of renal and prostate carcinoma with refractive index radiology

Giorgio Margaritondo

Having better edge enhancement and penetrating power, refractive index radiology is suitable for the imaging of weakly absorbing objects such as tissue specimens. In this study the potential of refractive index radiology was evaluated for the imaging of re ...

Wiley-Blackwell2007

Ancient administrative handwritten documents: X-ray analysis and imaging

Giorgio Margaritondo, Frédéric Kaplan, Fauzia Albertin

Handwritten characters in administrative antique documents from three centuries have been detected using different synchrotron X-ray imaging techniques. Heavy elements in ancient inks, present even for everyday administrative manuscripts as shown by X-ray ...

International Union of Crystallography2015

Semiconductors, general properties

Giorgio Margaritondo

This presentation starts with a general description of the electronic energy structure of insulators. This is the background of basic semiconductor features including the bands and the forbidden gap, the effective mass, the mobility and doping with donors ...

Elsevier2024

Explaining the physics of tsunamis to undergraduate and non-physics students

Giorgio Margaritondo

After the recent devastating tsunami in southern Asia, I tried to find a simple way to present the physics of this phenomenon to students-in particular, the origin of the dispersion relation and the consequent wave properties. Being unable to locate a suit ...

2005

Free-electron-laser coherent diffraction images of individual drug-carrying liposome particles in solution

Giorgio Margaritondo

Using the excellent performances of a SACLA (RIKEN/HARIMA, Japan) X-ray free electron laser (X-FEL), coherent diffraction imaging (CDI) was used to detect individual liposome particles in water, with or without inserted doxorubicin nanorods. This was possi ...

2018

Graphene nanoribbons produced by the oxidative unzipping of single-wall carbon nanotubes

Giorgio Margaritondo, Primoz Rebernik Ribic

Graphene nanoribbons were synthesized by oxidative unzipping of single-wall carbon nanotubes (SWCNTs). The nanoribbons produced from SWCNTs were characterized using FT-IR, Raman and X-ray photoelectron spectroscopy. For the morphological study of the produ ...

2010