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Concept

Luneburg lens

Publications associées (29)

Laser-based manufacturing of freeform glass micro-optics through topological transformation

Samuel Youcef Benketaf

Glass has been the material of choice for making optical elements, in large part due to its intrinsic properties: a temperature-dependent viscosity, which enables shaping the material into a broad variety of functional and artistic glassware. Silica glass ...

EPFL2024

Searching for Strong Gravitational Lenses

Frédéric Courbin, Cameron Alexander Campbell Lemon

Strong gravitational lenses provide unique laboratories for cosmological and astrophysical investigations, but they must first be discovered - a task that can be met with significant contamination by other astrophysical objects and asterisms. Here we revie ...

Springer2024

The impact of human expert visual inspection on the discovery of strong gravitational lenses

Frédéric Courbin, Hung-Hsu Chan, Martin Raoul Robert Millon, Benjamin Yvan Alexandre Clement, Karina Alexandra Rojas Olate, Elodie Marie Charlène Savary, Eric Gérard Guy Paic, Rémy Elie Joseph

We investigate the ability of human 'expert' classifiers to identify strong gravitational lens candidates in Dark Energy Survey like imaging. We recruited a total of 55 people that completed more than 25 per cent of the project. During the classification t ...

OXFORD UNIV PRESS2023

In situ detection of multitarget impurities on contact lens by electrochemical scanning probe

Fang Liu, Tzu-En Lin, Yingdi Zhu

Identifying multitarget impurities on contact lenses is challenging because traditional methods such as polymerase chain reaction cannot be used on the unknown target. Other sampling methods often require expensive antibodies or dyes. Therefore, this resea ...

ELSEVIER SCIENCE SA2023

TOCOSMO VIII. A key test of systematics in the hierarchical method of time-delay cosmography

Frédéric Courbin

The largest source of systematic errors in the time-delay cosmography method likely arises from the lens model mass distribution, where an inaccurate choice of model could in principle bias the value of H-0. A Bayesian hierarchical framework has been propo ...

EDP SCIENCES S A2022

SLITRONOMY: Towards a fully wavelet-based strong lensing inversion technique

Frédéric Courbin, Aymeric Alexandre Galan, Austin Chandler Peel, Rémy Elie Joseph

Strong gravitational lensing provides a wealth of astrophysical information on the baryonic and dark matter content of galaxies. It also serves as a valuable cosmological probe by allowing us to measure the Hubble constant independently of other methods. T ...

EDP SCIENCES S A2021

Camera Calibration Models and Methods for Corridor Mapping with UAVs

Jan Skaloud, Davide Antonio Cucci, Emmanuel Pierre Quentin Clédat

Camera calibration refers to the modeling of the relationship between the coordinates of object points and their projections on the image plane. This is usually done by parametric models that describe the physical properties of the lens systems and camera ...

2020

Koehler integrator device and application thereof in a multi-focal confocal microscope

Suliana Manley, Dora Mahecic, Kyle Michael Douglass

A Koehler integrator device (10) comprises a collimating lens (11) being arranged for collimating a light field created by an incoherent or partially coherent light source, a pair of planar first and second micro-lens arrays (12, 13) being arranged for rel ...

2020

Active Phase-Conjugating Rotman Lens With Reflection Amplifiers for Backscattering Enhancement

Pouyan Keshavarzian

Active retrodirective antenna arrays find a variety of use in applications involving wireless communication and sensing systems. This article presents a novel active version of the phase-conjugating Rotman lens with negative conductance amplifiers for appl ...

Institute of Electrical and Electronics Engineers2020

Leveraging wafer-level manufacturing process limitations to increase large scale fused silica microlens array uniformity

Toralf Scharf, Wilfried Noell, Raoul Kirner, Jeremy Béguelin

The wafer-level production of Fused Silica microlens arrays is limited by systematic process non-uniformities. The common molten resist-reflow process with subsequent dry-etching allows for manufacturing of microlens arrays on 200 mm wafers. A thorough pro ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Sparse Lens Inversion Technique (SLIT): lens and source separability from linear inversion of the source reconstruction problem

Frédéric Courbin, Rémy Elie Joseph

Strong gravitational lensing offers a wealth of astrophysical information on the background source it affects, provided the lensed source can be reconstructed as if it was seen in the absence of lensing. In the present work, we illustrate how sparse optimi ...

EDP SCIENCES S A2019

Are Photonic Nanojets Achromatic?

Toralf Scharf, Myun Sik Kim, Michail Symeonidis

In this work we study the evolution of the photonic nanojet (PNJ) phenomenon as the ratio of the sphere's diameter over the illumination wavelength changes, for microspheres with diameters from 2 mu m to 100 mu m. We measure the focal point position by usi ...

SPIE-INT SOC OPTICAL ENGINEERING2019

A SHARP view of H0LiCOW: H-0 from three time-delay gravitational lens systems with adaptive optics imaging

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon

We present the measurement of the Hubble constant, H-0, with three strong gravitational lens systems, We describe a blind analysis of both PG 1115+080 and 11E0435-1223 as well as an extension of our previous analysis of RXJ 1131-1231. For each lens, we com ...

OXFORD UNIV PRESS2019

The core of the massive cluster merger MACS J0417.5-1154 as seen by VLT/MUSE

Jean-Paul Richard Kneib, David Richard Harvey, Johannes Richard Cornelis Geerit Kruis

We present a multiwavelength analysis of the core of the massive galaxy cluster MACS J0417.5-1154 (z = 0.441). Our analysis takes advantage of Very Large Telescope/Multi-Unit Spectroscopic Explorer observations which allowthe spectroscopic confirmation of ...

OXFORD UNIV PRESS2019

Stepwise Luneburg Lens for Bloch Surface Waves

Myun Sik Kim, Babak Vosoughi Lahijani

In order to enlarge the capability for in-plane manipulation of the Bloch surface wave (BSW), we investigate 2D gradient index (GRIN) optical components using a finite-difference time-domain (FDTD) numerical method. To ease difficulties in fabrication to a ...

2018

AAM: An Assessment Metric of Axial Chromatic Aberration

Sabine Süsstrunk, Majed El Helou, Frederike Dümbgen

Knowledge of lens specifications is important to identify the best lens for a given capture scenario and application. Lens manufacturers provide many specifications in their data sheets, and multiple initiatives for testing and comparing different lenses c ...

2018

Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI). II. Environments and Line-of-Sight Structure of Strong Gravitational Lens Galaxies to z similar to 0.8

Hung-Hsu Chan

We investigate the local and line-of-sight (LOS) overdensities of strong gravitational lens galaxies using wide-area multiband imaging from the Hyper Suprime-Cam Subaru Strategic Program. We present 41. new definite or probable lens candidates discovered i ...

2018

Electromagnetic Waves in a Time Periodic Medium With Step-Varying Refractive Index

Romain Christophe Rémy Fleury, Theodoros Koutserimpas

We present an exact mathematical framework for electromagnetic wave propagation in periodically time-modulated media, in which the permittivity is homogenous and modulated in a step-varying fashion. By using Hill’s equation theory, we show that this proble ...

2018

Sparse Linear Inversion for Strong Gravitational Lenses Reconstruction, Component Separation from Morphological Component Analysis with Multiple Discrimination Criteria

Rémy Elie Joseph

Strong gravitational is a natural phenomenon that produces distorted images of distant galaxies due to massive galaxies or clusters, called deflectors or lenses, lying along the line of sight. Due to the mass of the deflector, and as a result of general re ...

EPFL2018

Scaling effect and its impact on wavelength-scale microlenses

Hans Peter Herzig, Toralf Scharf, Myun Sik Kim

We revisit the scaling laws in micro-optical systems to highlight new phenomena arising beyond a conventional optical regime, especially when the size of the system approaches to the operational wavelength. Our goal is to visualize the impact of the scalin ...

Spie-Int Soc Optical Engineering2017