Publications associées à Phase-contrast X-ray imaging

3D printed large amplitude torsional microactuators powered by ultrasound

Mahmut Selman Sakar, Mehdi Ali Gadiri, Junsun Hwang, Amit Yedidia Dolev

Here, we introduce a design, fabrication, and control methodology for large amplitude torsional microactuators powered by ultrasound. The microactuators are 3D printed from two polymers with drastically different elastic moduli as a monolithic compliant me ...

2024

Tangentially viewing phase contrast imaging for turbulence measurements in toroidal fusion devices

Stefano Coda

Phase contrast imaging (PCI) is an established and powerful technique for measuring density fluctuations in plasmas and has been successfully applied to several fusion devices. Rooted in a concept first developed for microscopy, PCI belongs to the category ...

2024

Tomographic microscopy of functionally graded polymer-derived SiCN ceramics with tunable gradients

Jürgen Brugger, Lorenz Hagelüken

Polymer-derived ceramics (PDCs) are a very attractive class of materials due to their excellent properties such as resistance to high temperatures and harsh environments, adjustability of mechanical and functional behavior, and compatibility with a broad r ...

Elsevier Sci Ltd2024

An adaptive phase field approach to 3D internal crack growth in rocks

Alexandra Roma Larisa Kushnir, Tao Xu, Michael Heap

Modeling the 3D internal crack under compression entails complex fracture mechanics (mode I-II-III fracture), resulting in substantial computational costs and challenges in characterizing fracture morphology characterization for Phase Field Method (PFM) si ...

2024

Reconstruction of Angstrom resolution exit-waves by the application of drift-corrected phase-shifting off-axis electron holography

Thierry Meyer, Victor Carle Adrien Boureau

Phase-shifting electron holography is an excellent method to reveal electron wave phase information with very high phase sensitivity over a large range of spatial frequencies. It circumvents the limiting trade-off between fringe spacing and visibility of s ...

Elsevier2023

Phase Retrieval: From Computational Imaging to Machine Learning: A tutorial

Michaël Unser, Thanh-An Michel Pham, Jonathan Yuelin Dong

Phase retrieval consists in the recovery of a complex-valued signal from intensity-only measurements. As it pervades a broad variety of applications, many researchers have striven to develop phase-retrieval algorithms. Classical approaches involve techniqu ...

2023

A synthetic phase-contrast imaging diagnostic with spatial filtering for gyrokinetic simulations

Stefano Coda, Stephan Brunner, Justin Richard Ball, Gabriele Merlo, Aylwin Iantchenko

A Phase-contrast imaging (PCI) diagnostic provides measurements of line-integrated electron density fluctuations. Localisation along the laser beam path can be achieved with a spatial filter that selects the wave-vector directions of the fluctuations contr ...

2023

Exploring Novel Modalities for Optical Diffraction Tomography

Amirhossein Saba Shirvan

In the past decade, optical diffraction tomography has gained a lot of attention for its ability to create label-free three-dimensional (3D) images of the refractive index distribution of biological samples using scattered fields measured through holograph ...

EPFL2023

Evaluating contrast sensitivity in early and intermediate age-related Macular Degeneration with the Quick Contrast Sensitivity Function

Michael Herzog, Simona Adele Garobbio

Purpose: The purpose of this study was to describe, validate, and compare the contrast sensitivity functions (CSFs) acquired with the novel quick CSF (qCSF) method from patients with early and intermediate age-related macular degeneration (eAMD and iAMD) a ...

2023

An optimal preconditioned FFT-accelerated finite element solver for homogenization

Till Junge, Ali Falsafi, Martin Ladecký

We generalize and provide a linear algebra-based perspective on a finite element (FE) ho-mogenization scheme, pioneered by Schneider et al. (2017)[1] and Leuschner and Fritzen (2018)[2]. The efficiency of the scheme is based on a preconditioned, well-scale ...

ELSEVIER SCIENCE INC2023

Quantum engineering and detection of advanced radiation beams

Veronica Leccese

Controlling and shaping radiation beams is fundamental for a better understanding of radiation-matter interaction and advancing experimental techniques for material characterization at high spatial resolution. In particular, the current trend in the miniat ...

EPFL2023

In situ monitoring of femtosecond laser-induced modifications in dielectrics

Olivier Bernard

Over the last decades, the progress made in the generation of laser pulses shorter than a picosecond (10^-12 s) has allowed us to reach extreme optical power intensities exceeding 10^15 W cm^-2. This tremendous power has triggered an abundance of original ...

EPFL2023

Automated Dual-Mode Cell Monitoring To Simultaneously Explore Calcium Dynamics and Contraction-Relaxation Kinetics within Drug-Treated Stem Cell-Derived Cardiomyocytes

Gerardo Turcatti, Benjamin Rappaz, Bokyoung Kim, Pierre Marquet

This manuscript proposes a new dual-mode cell imaging system for studying the relationships between calcium dynamics and the contractility process of cardiomyocytes derived from human-induced pluripotent stem cells. Practically, this dual-mode cell imaging ...

AMER CHEMICAL SOC2023

Near-wall hemodynamic parameters quantification in in vitro intracranial aneurysms with 7 T PC-MRI

Mohamed Farhat, Philippe Reymond

ObjectiveWall shear stress (WSS) and its derived spatiotemporal parameters have proven to play a major role on intracranial aneurysms (IAs) growth and rupture. This study aims to demonstrate how ultra-high field (UHF) 7 T phase contrast magnetic resonance ...

SPRINGER2023

Lock-in amplified differential phase contrast

Christophe Moser, Timothé Laforest, Damien Claude-Marie Loterie, Chiara Bonati

We introduce a lock-in method to increase the phase contrast in incoherent Differential Phase Contrast (DPC) imaging. The use of a smart pixel detector with in-pixel signal demodulation, paired with synchronized illumination, provides the basis of a bit-ef ...

SPIE-INT SOC OPTICAL ENGINEERING2022

Lock-in incoherent differential phase contrast imaging

Christophe Moser, Timothé Laforest, Damien Claude-Marie Loterie, Chiara Bonati

We introduce a lock-in method to increase the phase contrast in incoherent differential phase contrast (DPC) imaging. This method improves the phase sensitivity by the analog removal of the background. The use of a smart pixel detector with in-pixel signal ...

CHINESE LASER PRESS2022

High sensitivity, incoherent differential imaging

Chiara Bonati

Microscopic visualisation of optically transparent samples has been a topic of interest for several decades. Features such as density or chemical composition can influence the optical phase of transmitted light, and phase contrast can reveal these structur ...

EPFL2022

Stain-free identification of cell nuclei using tomographic phase microscopy in flow cytometry

Demetri Psaltis, Joowon Lim, Daniele Pirone

The accurate identification of the three-dimensional quantitative shape of a cell nucleus is now possible without fluorescent staining by applying computational segmentation to refractive index tomograms recorded in the flow cytometry mode. ...

Nature Publishing Group2022

Multicore fiber endoscope for phase imaging based on intensity recording using deep neural networks

Demetri Psaltis, Christophe Moser, Navid Borhani, Eirini Kakkava

The present invention is related to an endoscopic system for phase imaging, comprising a multicore waveguide (080), an optical system comprising at least one first light source (002), for illuminating the sample to be examined, a first camera (010) that is ...

2022

Phase Reconstruction of Low-Energy Electron Holograms of Individual Proteins

Klaus Kern, Stephan Rauschenbach, Sven Alexander Szilagyi, Hannah Julia Ochner

Low-energy electron holography (LEEH) is one of the few techniques capable of imaging large and complex three-dimensional molecules, such as proteins, on the single molecule level at subnanometer resolution. During the imaging process, the structural infor ...

AMER CHEMICAL SOC2022