Optical tomography at the microscopic scale by means of a numerical low coherence holographic technique

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In wave propagation problems, finite difference methods implemented on staggered grids are commonly used to avoid checkerboard patterns and to improve accuracy in the approximation of short-wavelength components of the solutions. In this study, we develop a mimetic finite difference (MFD) method on staggered grids for transport operators with divergence-free advective field that is proven to be energy-preserving in wave problems. This method mimics some characteristics of the summation-by-parts (SBP) operat

High-efficiency single-photon detection in the microwave domain is a key enabling technology for various quantum applications. However, the extremely low energy of microwave photons presents a fundamental challenge, preventing direct photon-to-charge conversion as achieved in optical systems using semiconductors. Here, we demonstrate continuous microwave photon detection with an efficiency approaching 70% in the single-photon regime. We use a hybrid system comprising a gate-defined double quantum dot (DQD)

The Thorpe and Mason (TM) model for calculating the mass lost from a sublimating snow grain is the basis of all existing small- and large-scale estimates of drifting snow sublimation and the associated snow mass balance of polar and alpine regions. We revisit this model to test its validity for calculating sublimation from saltating snow grains. It is shown that numerical solutions of the unsteady mass and heat balance equations of an individual snow grain reconcile well with the steady-state solution of th

In this paper we give a survey on various multiscale methods for the numerical solution of second order hyperbolic equations in highly heterogenous media. We concentrate on the wave equation and distinguish between two classes of applications. First we discuss numerical methods for the wave equation in heterogeneous media without scale separation. Such a setting is for instance encountered in the geosciences, where natural structures often exhibit a continuum of different scales, that all need to be resolve

This project presents the theoretical background in electrophysiology that is used as a basis in the development of numerical methods for the simulation of heart’s electrical activity. We discuss the mathematical models currently used in cardiac electrophysiology research to simulate the propagation of an action potential wave, and then focus on the description of the ionic currents. This study allows us to anticipate the numerical model sensitivity with regard to the discretization, with the aim of recover

Nanoparticles are interesting for biomedical imaging as novel non- fluorescent non-bleaching labels. We present the characterization of freely diffusing nanoparticles using third harmonic generation correlation spectroscopy by illumination with a focussed pulsed femtosecond laser. We present the optical system as well as first spectroscopic results on nanoparticles.

Objectives: We are interested in the numerical simulation of the anastomotic region comprised between outflow canula of LVAD and the aorta. Segmentation, geometry reconstruction and grid generation from patient specific data remain an issue because of the variable quality of DICOM images, in particular CT-scan (e.g. metallic noise of the device, non-aortic contrast phase). We propose a general framework to overcome this problem and create suitable grids for numerical simulations. Methods: Preliminary treatm

Cardiovascular diseases have a major impact in Western countries. Mathematical models and numerical simulations can help the understanding of physiological and pathological processes, complementing the information provided to medical doctors by medical imaging and other non-invasive means, and opening the possibility of a better diagnosis and more in-depth surgical planning.This book offers a mathematically sound and up-to-date foundation to the training of researchers, and serves as a useful reference for

With the use of a Bessel-like illumination beam produced by an axicon lens an extended depth of field can be achieved. The resulting illumination pattern exhibits a strong central lobe extending over 300um along the optical axis without diffraction. Here we present a fast digital focusing algorithm to correct for remaining out of focus artifacts, manifest in sidelobes for out of focus scatterers, due to the decoupled Gaussian detection. The waist of the detection in the focal plane is 2.1um, with a Rayleigh

Conventional laboratory odometer tests were performed to determine the consolidation behaviour of Champlain Sea clays. Odometer permeability tests were also completed for each sample between two of the consolidation steps. The tests lasted 20 to 24 days. The goal of this project was to design and implement a numerical modelling approach to reduce the number of laboratory permeability tests required for each sample, thereby reducing the test duration to 12-14 days.

A 3D imager is presented capable of computing the depth map as well as the intensity scale of a given scene. The heart of the system is a two-dimensional array of single photon avalanche diodes fabricated in standard CMOS technology. The diodes exhibit low noise equivalent power, high dynamic range and superior linearity. The 3D imager achieves sub-millimetric precision at depth-of-field of a few meters. It operates using a standard LASER source pulsed at 50MHz with 40mW peak power and requires no mechanica

Low coherence, digital holographic microscopy (LCDHM) is a new 3D imaging technique combining the advantages of digital holographic microscopy with those of reduced coherence interferometry. This gives the possibility to perform tomography of 3D objects while maintaining the excellent performances of DHM. A tomographic depth resolution of 11 mum has been achieved as a proof of principle. Images of the epithelial cells of the porcine cornea are presented.

We have measured the ultrafast resonant Rayleigh scattering from quantum-well excitons using Fourier-transform spectral interferometry. The experiment simultaneously measures a statistically significant number of speckles with 100 fs temporal resolution. We show that theories based on ensemble averaging can he compared directly with the experimental resonant Rayleigh scattering dynamics.

The computation of glacier movements leads to a system of nonlinear partial differential equations. The existence and uniqueness of a weak solution is established by using the calculus of variations. A discretization by the finite element method is done. The solution of the discrete problem is proved to be convergent to the exact solution. A first simple numerical algorithm is proposed and its convergence numerically studied.

Digital holograms are recorded by a CCD camera and are numerically reconstructed, in intensity and phase, by means of an algorithm which calculates their discrete Fresnel transform. By using a low-coherence source, the tomography of a 3D scene can be performed without lateral scanning with a depth resolution equal to the coherence length and a lateral resolution equal to the diffraction limit of the microscope objective used

Optical tomography at the microscopic scale by means of a numerical low coherence holographic technique

Chat with Graph Search

Mimetic finite difference schemes for transport operators with divergence-free advective field and applications to plasma physics

Tunable high-efficiency microwave photon detector based on a double quantum dot coupled to a superconducting high-impedance cavity

Revisiting the Thorpe-Mason model for calculating sublimation of saltating snow

MATHICSE Technical Report : Multiscale methods for wave problems in heterogeneous media

Phenomenological and physiological approaches in the study of cardiac alternans: Theoretical background, mathematical modeling and numerical simulations

Characterization of Nanoparticles Using Non-linear Correlation Spectroscopy

Segmentation and Grid Generation for Numerical Simulations of VAD Connections with Patientspecific Data

Cardiovascular Mathematics

Enhancement of extended depth of field by digital focusing

Consolidation œdométrique d’argile Champlain. Détermination directe et indirecte de la conductivité hydraulique en fonction de l’indice des vides.

Toward a 3-D Camera Based on Single Photon Avalanche Diodes

Low coherence digital holographic tomography

Speckle-averaged resonant Rayleigh scattering from quantum-well excitons

A strongly nonlinear problem arising in glaciology

Optical tomography by means of a numerical low-coherence holographic technique