Publications associées à Objectif optique

Femtosecond laser-induced modifications and self-organization in complex glass systems

Ultrashort laser pulses, i.e., pulses emitted shorter than a picosecond, can tailor material properties by introducing permanent modifications locally in three dimensions. Remarkably, under a certain exposure condition, these modifications are accompanied ...

EPFL2023

Functional neuroimaging options for tinnitus

Patrick Karl Alois Neff

Background: The pathophysiology behind tinnitus is still not well understood. Different imaging methods help in the understanding of the complex relationships that lead to the perception of tinnitus.Objective: Herein, different functional imaging methods t ...

SPRINGER2023

Assessment of the hydromorphological effectiveness of sediment augmentation measures downstream of dams

Giovanni De Cesare, Christian Mörtl

This article presents assessment methods for the hydromorphological effectiveness of sediment augmentation measures downstream of dams. First, we describe different ways of quantifying hydromorphological effectiveness based on typical objectives of sedimen ...

CRC Press/Balkema2023

Estimating Nonplanar Flow from 2D Motion-blurred Widefield Microscopy Images via Deep Learning

Michael Stefan Daniel Liebling, Adrian Shajkofci

Optical flow is a method aimed at predicting the movement velocity of any pixel in the image and is used in medicine and biology to estimate flow of particles in organs or organelles. However, a precise optical flow measurement requires images taken at hig ...

IEEE2021

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

ON THE DESIGN AND OPTIMIZATION OF WIDE ANGLE DIFFRACTIVE OPTICAL ELEMENTS

Dong Cheon Kim

Diffractive optical elements (DOEs) which consist of microstructure surface relief permit the generation of the spatial distribution of light beams by using a single element. Due to their compact size, design flexibility, and mass productivity, they are us ...

EPFL2021

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

Correction of spherical surface measurements by confocal microscopy

Toralf Scharf, Wilfried Noell, Jeremy Béguelin

Refractive microlenses are nowadays widely used in optical systems. Characterizing their surface is essential to ensure their quality and to optimize their fabrication process. This is realized by optical surface profilers thanks to their vertical resoluti ...

2020

Optical characterization of high numerical aperture microlenses for quality assessment and fabrication process optimization

Toralf Scharf, Wilfried Noell, Jeremy Béguelin

Accurate characterization of high numerical aperture aspheric microlenses currently is a nonstandard procedure that remains an open challenge. Here, we present and discuss a characterization method based on interferometric and point spread function measure ...

OPTICAL SOC AMER2020

Realistic Constrained Multi-Objective Optimization Benchmark Problems from Design

Jürg Alexander Schiffmann, Cyril Picard

Multi-objective optimization is increasingly used in engineering to design new systems and to identify design trade-offs. Yet, design problems often have objective functions and constraints that are expensive and highly non-linear. Combinations of these fe ...

2020

3D nanometrology of transparent objects by phase calibration of a basic bright-field microscope for multiple illumination apertures

Martinus Gijs, Daniel Migliozzi, Bingying Zhao

Optical retrieval of the structure of transparent objects at the nanoscale requires adapted techniques capable of probing their interaction with light. Here, we considered a method based on calibration of the defocusing with partially coherent illumination ...

2020

On the assessment of aspheric refractive microlenses

Jeremy Béguelin

Refractive microlenses and microlens arrays are key components for many applications such as optical data communication, laser and medical devices, or cameras. In particular, refractive micro-optics enables the miniaturization of high-tech systems but also ...

EPFL2020

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

Raman imaging through multimode sapphire fiber

Demetri Psaltis, Christophe Moser, Damien Claude-Marie Loterie, Georgia Konstantinou, Sunan Deng

We report on a sapphire fiber Raman imaging probe's use for challenging applications where access is severely restricted. Small-dimension Raman probes have been developed previously for various clinical applications because they show great capability for d ...

OPTICAL SOC AMER2019

Custom Adapter For Extended Field-Of-View Microsphere-Based Scanning Super-Resolution Microscopy

Martinus Gijs, Gergely Huszka

We present a dielectric microsphere-based super resolution optical microscope that can image a sample beyond the classical diffraction limit [1]. The super resolution imaging capability of a single microsphere normally is restricted to an area of similar t ...

IEEE2018

Compact lensless digital holography

Manon Rostykus

Microscopy is of high interest for biology since it allows imaging features that are too small to be seen with naked eyes. However, cells are mostly transparent to visible and infrared light which makes it difficult to see with a traditional microscope. To ...

EPFL2018

Aberrations analysis of a Focused Plenoptic Camera

Toralf Scharf, Alessandro Grosso

A Focused Plenoptic Camera in Galilean configuration is studied and its aberrations behavior is interpreted with the Nodal Aberration Theory (NAT). Sequential ray tracing is applied to individual optical channels constituted by the camera objective and ind ...

2018

Geodesic Convolutional Shape Optimization

Pascal Fua, François Fleuret, Pierre Bruno Baqué, Edoardo Remelli

Aerodynamic shape optimization has many industrial applications. Existing methods, however, are so computationally demanding that typical engineering practices are to either simply try a limited number of hand-designed shapes or restrict oneself to shapes ...

2018

Dielectric-sphere-based microsystem for optical super-resolution imaging

Gergely Huszka

Well-established imaging techniques proved that features below the diffraction limit can be observed optically using so-called super-resolution microscopies, which overcome Abbe's resolution limit. In traditional far-field microscopy, the introduction of f ...

EPFL2018

Turning a normal microscope into a super-resolution instrument using a scanning microlens array

Martinus Gijs, Gergely Huszka

We report dielectric microsphere array-based optical super-resolution microscopy. A dielectric microsphere that is placed on a sample is known to generate a virtual image with resolution better than the optical diffraction limit. However, a limitation of s ...

Nature Research2018