Publications associées à Oculaire

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

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

Toralf Scharf, Wilfried Noell, Raoul Kirner, Jeremy Béguelin

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

Almost surely constrained convex optimization

Volkan Cevher, Ahmet Alacaoglu

We propose a stochastic gradient framework for solving stochastic composite convex optimization problems with (possibly) infinite number of linear inclusion constraints that need to be satisfied almost surely. We use smoothing and homotopy techniques to ha ...

2019

Geometric calibration of Colour and Stereo Surface Imaging System of ESA's Trace Gas Orbiter

François Fleuret, Anton Ivanov, Stepan Tulyakov, Nicolas Thomas, Thomas Weigel

There are many geometric calibration methods for "standard" cameras. These methods, however, cannot be used for the calibration of telescopes with large focal lengths and complex off-axis optics. Moreover, specialized calibration methods for the telescopes ...

Elsevier2018

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

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

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

Martinus Gijs, Raphaël Etienne Jean Trouillon, Hui Yang, 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

Refraction limit of miniaturized optical systems: a ball-lens example

Hans Peter Herzig, Roland Andreas Bitterli, Toralf Scharf, Wilfried Noell, Myun Sik Kim

We study experimentally and theoretically the electromagnetic field in amplitude and phase behind ball-lenses across a wide range of diameters, ranging from a millimeter scale down to a micrometer. Based on the observation, we study the transition between ...

Optical Society of America2016

Organic-inorganic-hybrid-polymer microlens arrays with tailored optical characteristics and multi-focal properties

Jürgen Brugger, Victor Javier Cadarso Busto, Loïc Jacot-Descombes

Plano-convex microlens arrays of organic-inorganic polymers with tailored optical properties are presented. The fine-tuning of each microlens within an array is achieved by confining inkjet printed drops of the polymeric ink onto pre-patterned substrates. ...

Optical Society of America2015

Curved Holographic Combiner for Color Head Worn Display

Jürgen Brugger, Christophe Moser, Eric Tremblay, Victor Javier Cadarso Busto, Jonas Grossenbacher, Arnaud Mader, Seyedpayam Vahdati

A volume hologram recorded with a lens array is proposed as a color transflective screen for Head Worn Display (HWD) systems. Design, fabrication as well as proof of concept are reported. Light from a single MEMS-based projector is efficiently diffracted t ...

Ieee-Inst Electrical Electronics Engineers Inc2014

On Micro Optical Elements for Efficient Light Diffusion

Roland Andreas Bitterli

Efficient light management is one of the key issues in modern energy conversion systems, be it to collect optical power or to redistribute light generated by high power light emitters. This thesis touches mainly on the subject of efficient light redistribu ...

EPFL2013

Real-time Implementation of Gaussian Image Blending in a Spherical Light Field Camera

Alexandre Schmid, Yusuf Leblebici, Vladan Popovic, Hossein Afshari

Panoptic is a custom spherical light field camera used as a polydioptric system where imagers are distributed over a spherical geometry, each having its own vision of the surrounding and a distinct focal plane. The spherical light field camera records ligh ...

Ieee2013

Binary Compressed Imaging

Michaël Unser, Aurélien Bourquard

Compressed sensing can substantially reduce the number of samples required for conventional signal acquisition at the expense of an additional reconstruction procedure. It also provides robust reconstruction when using quantized measurements, including in ...

Ieee-Inst Electrical Electronics Engineers Inc2013

Real-time FPGA implementation of linear blending vision reconstruction algorithm using a spherical light field camera

Alexandre Schmid, Yusuf Leblebici, Vladan Popovic, Hossein Afshari, Abdulkadir Akin

A custom spherical light-field camera used as a polydioptric system where imagers are distributed over a spherical geometry, each having its own vision of the surrounding and distinct focal plane. The spherical light-field camera is also an omnidirectional ...

2012

High Intensity Beam Issues in the CERN Proton Synchrotron

Sandra Aumon

This PhD work is about limitations of high intensity proton beams observed in the CERN Proton Synchrotron (PS) and, in particular, about issues at injection and transition energies. With its 53 years, the CERN PS would have to operate beyond the limit of i ...

EPFL2012

Hybrid polymer microlens arrays with high numerical apertures fabricated using simple ink-jet printing technique

Jürgen Brugger, Edoardo Charbon, Vahid Fakhfouri, Dmitri Boiko, Joo Yeon Kim, Nils Benedict Brauer

Microlens arrays fabricated by a direct ink-jet printing of UV-curable hybrid polymer are reported. A periodic pattern of polymer drops was ink-jet printed on the surface-treated glass substrate and cured in the UV-light. Using this simple technique, we de ...

2011

On the Characteristics of Highly Confined Light Fields : A High-Resolution Interference Microscopy Study

Myun Sik Kim

The Investigation of highly confined light fields created by different mechanisms, such as refraction, diffraction, and scattering, are the main subject of this thesis. We distinguish a specific scattering phenomenon of dielectric microspheres from general ...

EPFL2011

Arrays of microlenses with variable focal lengths fabricated by restructuring polymer surfaces with an ink-jet device

Ramon Pericet Camara

We report of a method for fabricating two-dimensional, regular arrays of polymer microlenses with focal lengths variable between 0.2 and 4.5 mm. We first make concave microlenses by ink-jetting solvent on a polymer substrate with a commercial drop-on-deman ...

Optical Society of America2007

Miniaturized optical tweezer array with an array of reflective elements for reflecting the light back to a focal area

René Salathé, Fabrice Merenda, Guy Delacrétaz, Gerben Boer

Apparatus for forming a single or a plurality of threedimensional optical traps, the apparatus comprising: a. A collimated light source that is directed onto an array of focalizing refractive or diffractive elements providing a single or a plurality of foc ...

2007

Extended focus depth for Fourier domain optical coherence microscopy

Theo Lasser, Martin Villiger, Rainer Leitgeb, Lukas Steinmann, Adrian Bachmann

We report on a new detection scheme for Fourier domain optical coherence microscopy that exhibits high transverse resolution along an axially extended focal range. Nearly constant transverse resolution of ∼1.5 μm along a focal range of 200 μm is experiment ...

2006