Publications related to Level-line moirés by superposition of cylindrical microlens gratings

Structured light generation by refractive-diffractive micro optical array illuminators

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

Moiré effects produced by superpositions of micro-lens arrays

Thomas Walger

Moiré effects result from the superimposition of repetitive structures. The beauty of these moirés comes from the fact that macroscopic shapes seem to appear from the superposition of layers containing microscopic patterns. In addition, the moirés are dyna ...

EPFL2020

Precise and accurate image-based measurements of optical material properties

Marjan Shahpaski

The appearance of objects is governed by how they reflect, transmit and absorb the light they receive. That, in turn, depends on the material's internal structure, surface structure, and viewing and illumination directions. Changes in those characteristics ...

EPFL2020

edxia: Microstructure characterisation from quantified SEM-EDS hypermaps

Karen Scrivener, Fabien Jacques Michel Georget, William Wilson

The characterisation of cement paste microstructure is an important step towards understanding durability mechanisms in cementitious materials. Scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) is a widely used technique ...

Pergamon-Elsevier Science Ltd2020

Phase resolved characterization of nanoscale features in optical microstructures

Michail Symeonidis

In this study, we apply interferometric microscopy to study the phase, alongside the intensity, of the light field transmitted through a wide variety of samples. Additionally, we conduct those interferometric measurements at different wavelengths within th ...

EPFL2019

Visbrain: A Multi-Purpose GPU-Accelerated Open-Source Suite for Multimodal Brain Data Visualization

Raphaël Vallat, Christian O'Reilly

We present Visbrain, a Python open-source package that offers a comprehensive visualization suite for neuroimaging and electrophysiological brain data. Visbrain consists of two levels of abstraction: (1) objects which represent highly configurable neuroori ...

2019

Transition of optical regime in miniaturized optical systems: light interactions beyond the refraction limit

Hans Peter Herzig, Myun Sik Kim, Toralf Scharf

We investigate the transition of optical regimes of miniaturized optical systems using two canonical examples, where the refraction of light limits the system performance. A ball-lens and a solid immersion lens (SIL) are considered, whose refractive respon ...

Spie-Int Soc Optical Engineering2016

Super-Resolution Imaging of a Dielectric Microsphere Is Governed by the Waist of Its Photonic Nanojet

Martinus Gijs, Hui Yang, Raphaël Etienne Jean Trouillon, Gergely Huszka

Dielectric microspheres with appropriate refractive index can image objects with super-resolution, that is, with a precision well beyond the classical diffraction limit. A microsphere is also known to generate upon illumination a photonic nanojet, which is ...

American Chemical Society2016

Sampling Models in Light Fields

Zhou Xue

What is the actual information contained in light rays filling the 3-D world? Leonardo da Vinci saw the world as an infinite number of radiant pyramids caused by the objects located in it. Nowadays, the radiant pyramid is usually described as a set of ligh ...

EPFL2016

Towards an incoherent off-axis digital holographic microscope

Frédéric Montfort, Christian Depeursinge

We propose and experimentally demonstrate a system in which off-axis digital holographic microscopy is realized using a broadband illumination source. Single-shot holographic measurements are enabled, while the coherence noise is removed thanks to the broa ...

Spie-Int Soc Optical Engineering2015

Measurement of in-plane and out-of-plane displacements and strains using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rishikesh Dilip Kulkarni

The paper proposes a non-destructive method for simultaneous measurement of in-plane and out-of-plane displacements and strains undergone by a deformed specimen from a single moire fringe pattern obtained on the specimen in a dual beam digital holographic ...

Taylor & Francis2014

Beating Shapes Relying on Moire Level Lines

Roger Hersch, Sylvain Chosson

We consider the problem of obtaining a recognizable shape as superposition moire of two line gratings. The method we propose generates moire lines located between the shape foreground and background centers and the shape boundaries. Upon relative displacem ...

Association for Computing Machinery2014

Simultaneous measurement of in-plane and out-of-plane displacements using pseudo-Wigner-Hough transform

Pramod Rastogi, Rishikesh Dilip Kulkarni

A new method based on pseudo-Wigner-Hough transform is proposed for the simultaneous measurement of the in-plane and out-of-plane displacements using digital holographic moire. Multiple interference phases corresponding to the in-plane and out-of-plane dis ...

Optical Society of America2014

Phase Anomalies in Micro-Optics

Hans Peter Herzig, Myun Sik Kim, Toralf Scharf

We present a comprehensive review on the latest research activities that explore the Gouy phase and indicate the recent experimental progresses for its observations in studies that rely on a longitudinal-differential interferometer. The latter is a far-fie ...

Elsevier, Amsterdam2013

An old tool and a new challenge for depicting antenna array radiation patterns

Juan Ramon Mosig

This paper is intended for teachers and students dealing with antenna engineering. Graphical tools have historically been used for illustrating many basic features of radiation patterns, such as the position and number of secondary lobes, null angles, and ...

Institute of Electrical and Electronics Engineers2011

Simultaneous multidimensional deformation measurements using digital holographic moiré

Pramod Rastogi, Sai Siva Gorthi, Rajshekhar Gannavarpu

This paper proposes an elegant technique for the simultaneous measurement of in-plane and out-of-plane displacements of a deformed object in digital holographic interferometry. The measurement relies on simultaneously illuminating the object from multiple ...

Optical Society of America2011

Extended Focus Optical Coherence Microscopy : Theory and Application

Martin Villiger

Optical coherence tomography (OCT) is an interferometric imaging technique that can provide depth resolved cross-sectional views of biological tissue. OCT employs light with low temporal and yet high spatial coherence. The sample is illuminated point by po ...

EPFL2010

Iterative method for zero-order suppression in off-axis digital holography

Christian Depeursinge, Nicolas Pavillon, Cristian Arfire

We propose a method to suppress the so-called zero-order term in a hologram, based on an iterative principle. During the hologram acquisition process, the encoded information includes the intensities of the two beams creating the interference pattern, whic ...

Optical Society of America2010

Endoscopic low coherence interferometry applied to tri-dimensional contouring of upper airways

Yves Delacrétaz

This thesis presents a novel approach for optical tri-dimensional contouring, requiring only one acquisition to extract a contour depth. It is based on an interferometric setup, using a reduced coherence light source, and is fully adaptable to endoscopic p ...

EPFL2009

Governing the speed of a light signal in optical fibers : Brillouin slow and fast light

Sang Hoon Chin

Dynamic control of the speed of a light signal, based on stimulated Brillouin scattering in optical fibers, was theoretically studied and also experimentally demonstrated as the core object of this thesis. To date, slow light based on stimulated Brillouin ...

EPFL2009