Publications associées à Acquisition of multiple phase derivatives from a single frame in digital holographic interferometry

3D diffractive optics for linear interconnects and nonlinear processing

The optical domain presents potential avenues for enhancing both computing and communication due to its inherent properties of bandwidth, parallelism, and energy efficiency. This research focuses on harnessing 3-Dimensional (3D) diffractive optics for nove ...

EPFL2024

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

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

Computationally Efficient Synchrophasor Estimation: Delayed In-Quadrature Interpolated DFT

Mario Paolone, Cesar Garcia Veloso

The paper proposes a synchropahsor estimation (SE) algorithm that leverages the use of a delayed in-quadrature complex signal to mitigate the self-interference of the fundamental tone. The estimator, which uses a three-point IpDFT combined with a three-cyc ...

2024

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

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

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

Practical computational imaging by use of spatiotemporal light modulation: from simulations to applications in biological microscopy

François Thierry M Marelli

Optical microscopy is an essential tool for biologists, who are often faced with the need to overcome the spatial and temporal resolution limitations of their devices to capture finer details. As upgrading imaging hardware is expensive, computational metho ...

EPFL2023

Percolation and phase behavior in cellulose nanocrystal suspensions from nonlinear rheological analysis

Tiffany Abitbol

We examine the influence of surface charge on the percolation, gel-point and phase behavior of cellulose nanocrystal (CNC) suspensions in relation to their nonlinear rheological material response. Desulfation decreases CNC surface charge density which lead ...

ELSEVIER SCI LTD2023

Microscopic Digital Image Correlation Analysis of Strain Distributions in Stainless Steel 316L Induced by Multiaxial Cyclic Loading

Elif Cansu Kursun

Fatigue damage in materials results in localized strain at the microstructural level. In many engineering components of the cooling circuits of nuclear power plants, where austenitic steels are used, the material experiences multiaxial cyclic loading, eith ...

EPFL2023

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

Optical Diffraction Tomography Using Nearly In-Line Holography with a Broadband LED Source

Demetri Psaltis, Ahmed Ayoub, Abhijit Roy

We present optical tomography methods for a 3D refractive index reconstruction of weakly scattering objects using LED light sources. We are able to record holograms by minimizing the optical path difference between the signal and reference beams while sepa ...

MDPI2022

Lock-in amplified differential phase contrast

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

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

Advanced Techniques in Optical Diffraction Tomography

Ahmed Bassam Sayed Ayoub Mohamed Emam

In this thesis, we study the 3 challenges described above. First, we study different reconstruction techniques and assess the fidelity of each reconstruction results by means of structured illumination and phase conjugation. By reconstructing the 3D refrac ...

EPFL2022

Glass-in-glass infiltration for 3D micro-optical composite components

Yves Bellouard, Andreas Mortensen, Jérôme Faist, Enrico Casamenti, Luciano Borasi, Gözden Torun, Mathieu Bertrand

Chalcogenide glass exhibits a wide transmission window in the infrared range, a high refractive index, and nonlinear optical properties; however, due to its poor mechanical properties and low chemical and environmental stability, producing three-dimensiona ...

2022

Structured light generation by refractive-diffractive micro optical array illuminators

Maryam Yousefi

Structured light generation having broad applications in different optical fields, is the topic of this thesis. Our structured light generation strategy is based on applying periodic microoptical elements at the refraction-diffraction limit, under a focuse ...

EPFL2021

In-operando dynamic visualization of flow through porous preforms based on X-ray phase contrast imaging

Véronique Michaud, Baris Çaglar, Helena Luisa Teixido Pedarros

Direct visualization is often sought to elucidate flow patterns and validate models to predict the filling kinetics during processes whereby a liquid resin infiltrates a textile porous preform. Here, X-ray phase contrast interferometry is evaluated to imag ...

2021

Polarization-sensitive optics diffraction tomography

Demetri Psaltis, Ahmed Ayoub, Joowon Lim, Elizabeth Elena Antoine, Amirhossein Saba Shirvan

Polarization of light has been widely used as a contrast mechanism in two-dimensional (2D) microscopy and also in some three-dimensional (3D) imaging modalities. In this paper, we report the 3D tomographic reconstruction of the refractive index (RI) tensor ...

2021

Phase calibration of a basic bright-field microscope for 3D metrology of transparent samples at the nanoscale

Martinus Gijs, Daniel Migliozzi, Bingying Zhao

Optical retrieval of the structure of transparent objects at the nano-scale requires adapted methods capable of probing their interaction with suitable light. Scattering events, for instance, depend on the content and the arrangement of the medium encounte ...

SPIE-INT SOC OPTICAL ENGINEERING2021

Robust Phase Unwrapping via Deep Image Prior for Quantitative Phase Imaging

Matthias Lütolf, Michaël Unser, Nathalie Brandenberg, Thanh-An Michel Pham, Fangshu Yang

Quantitative phase imaging (QPI) is an emerging label-free technique that produces images containing morphological and dynamical information without contrast agents. Unfortunately, the phase is wrapped in most imaging system. Phase unwrapping is the comput ...

2021