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

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

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

Fluorescence microscopy: A statistics-optics perspective

Aleksandra Radenovic

Fundamental properties of light unavoidably impose features on images collected using fluorescence microscopes. Accounting for these features is often critical in quantitatively interpreting microscopy images, especially those gathering information at scal ...

Amer Physical Soc2024

A new versatile hybrid MEMS technology for high sensitivity, fluid proof sensing applications

Matthias Neuenschwander

The field of micro electromechanical systems (MEMS) evolved from the microelectronic industry and the technologies developed to fabricate integrated circuits. As a result, MEMS are commonly fabricated on silicon wafers. The development of MEMS has been dri ...

EPFL2022

ON WAVEFRONT ABERRATIONS IN ASYMMETRIC AND MULTIPLE APERTURE OPTICAL SYSTEMS

Alessandro Grosso

The present work deals with monochromatic wavefront aberrations in optical systems without symmetries. The treatment begins with a class of systems characterized by misaligned spherical surfaces whose behavior is analyzed using the wavefront aberration exp ...

EPFL2021

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

High-Resolution Multi-Spectral Imaging With Diffractive Lenses and Learned Reconstruction

Oguzhan Fatih Kar, Can Deniz Bezek

Spectral imaging is a fundamental diagnostic technique with widespread application. Conventional spectral imaging approaches have intrinsic limitations on spatial and spectral resolutions due to the physical components they rely on. To overcome these physi ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

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

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

Wilfried Noell, Toralf Scharf, 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

Correction of spherical surface measurements by confocal microscopy

Wilfried Noell, Toralf Scharf, 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

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

Stretchable Kirigami Components for Composite Meso-Scale Robots

Jamie Paik, Amir Firouzeh, Tatsuya Higashisaka

Layer-by-layer manufacturing of composite mechanisms allows fast and cost-effective fabrication of customized robots in millimeter and centimeter scales which is promising for research fields that rely on frequent and numerous physical iterations. Due to t ...

2020

Specification of aspherical surfaces used as refractive elements in micro-optical systems

Wilfried Noell, Toralf Scharf, Jeremy Béguelin

The optical performance of refractive plano-convex microlenses is mainly related to the quality of their (a)spherical surface. An efficient tolerancing of this surface is a key step towards the manufacturing of high quality microlenses. However, we demonst ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Improvements on the uniformity of large-area microlens arrays in Fused Silica

Wilfried Noell, Toralf Scharf, Jeremy Béguelin, Raoul Kirner

The uniformity of large microlens arrays in Fused Silica is governed by the production process. It comprises photolithographic patterning of a spin-coated layer of photoresist on a 200mm wafer with a molten resist reflow process and subsequent dry etching. ...

OPTICAL SOC AMER2019

Are Photonic Nanojets Achromatic?

Myun Sik Kim, Toralf Scharf, 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

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

Ultrasensitive hyperspectral imaging and biodetection enabled by dielectric metasurfaces

Volkan Cevher, Hatice Altug, Filiz Yesilköy, Andreas Tittl, Yasaman Jahani, Eduardo Romero Arvelo, Mingkai Liu

Metasurfaces based on resonant subwavelength photonic structures enable novel ways of wavefront control and light focusing, underpinning a new generation of flat-optics devices. Recently emerged all-dielectric asymmetric metasurfaces, composed of arrays of ...

Nature Publishing Group2019

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

Assessing microlens quality based on 3D irradiance measurement at the focal spot area

Wilfried Noell, Toralf Scharf, Jeremy Béguelin, Michail Symeonidis

During the fabrication process of microlenses, characterization is essential for two purposes: evaluate the optical quality of the element and provide surface information feedback for process optimization. However, no technique can fulfill these two object ...

2018

AAM: An Assessment Metric of Axial Chromatic Aberration

Sabine Süsstrunk, Frederike Dümbgen, Majed El Helou

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