Publications associées à Quantification of Bulk Densification in Fused Silica Induced by Femtosecond Laser Exposure in the Sub-50 fs Regime

Modulating the Surface Properties of Lithium Niobate Nanoparticles by Multifunctional Coatings Using Water-in-Oil Microemulsions

Sandrine Gerber, Adrian Stefan Gheata, Manon Inès Noëlla Wittwer, Alessandra Spada

Inorganic nanoparticles (NPs) have emerged as promising tools in biomedical applications, owing to their inherent physicochemical properties and their ease of functionalization. In all potential applications, the surface functionalization strategy is a key ...

2023

Femtosecond laser-shockwave induced densification in fused silica

Yves Bellouard, Pieter Vlugter, Arunkrishnan Radhakrishnan, Julien Gilles Edgar Gateau

A tightly focused femtosecond laser-beam in the non-ablative regime can induce a shockwave sufficiently intense to reach local pressures in the giga-Pascal range or more. In a single beam configuration, the location of the highest-pressure zone is nested w ...

2022

Abnormal temperature dependent elastic properties of fused silica irradiated by ultrafast lasers

Yves Bellouard, Pieter Vlugter

Materials with thermal-invariant elastic properties are of interest for resonant device frequency and dimensional stability of precision devices. Here, we demonstrate that the temperature coefficient of elasticity (TCE) of amorphous silica can be locally r ...

2022

Effect of femtosecond laser-induced high pressure on fused silica polymorphism

Arunkrishnan Radhakrishnan

High-pressure studies in silica are of great interest to earth and planetary sciences. Highpressure phases are rarely found in nature as a result of shock events like meteorite impacts or volcanic events in nature. Recreating these phases remains a challen ...

EPFL2022

Strong silicon oxide inclusions in iron

Andreas Mortensen, Léa Deillon, Alejandra Inés Slagter, Joris Pierre Everaerts

Oxide inclusions are ubiquitous in steel and are known to affect, generally in a negative sense, the mechanical performance of steel products. Micromechanical properties of those phases are therefore important, yet they have remained largely unexplored. We ...

2022

Ultrafast laser interaction with transparent multi-layer SiO2/Si3N4 films

Yves Bellouard, Ruben Ricca, Victor Carle Adrien Boureau

We investigate the use of ultrafast lasers exposure to induce localized crystallization and elemental redistribution in amorphous dielectric multi-layers, composed of alternating Si3N4 and SiO2 layers of sub-micrometer thickness. Specifically, we report on ...

2021

Investigation of femtosecond laser-tuned thermomechanical properties of fused silica

Pieter Vlugter

The thermomechanical properties of materials are among the most important properties for designing precision instruments, in particular for devices seeking high-dimensional stability, invariant temperature-elastic properties or low thermoelastic losses. De ...

EPFL2020

Impact of oxygen content in powders on the morphology of the laser molten tracks in preparation for additive manufacturing of silicon

Patrik Willi Hoffmann, Lucas Güniat, Marc Leparoux

Powder additive pulsed Nd:YAG laser (wavelength 1064 nm), with the aim of preparing AM of such material. The influence of oxygen content in the initial silicon powders on the continuous tracks morphology was investigated. It was found that the initial oxyg ...

ELSEVIER2020

Ultrafast carbothermal reduction of silica to silicon using a CO2 laser beam

Jaeki Jeong

We report the extraction of silicon via a carbothermal reduction process using a CO2 laser beam as a heat source. The surface of a mixture of silica and carbon black powder became brown after laser beam irradiation for a few tens of seconds, and clear peak ...

NATURE RESEARCH2020

A Monolithic Micro-Tensile Tester for Investigating Silicon Dioxide Polymorph Micromechanics, Fabricated and Operated Using a Femtosecond Laser

Yves Bellouard, Christos Edouardos Athanasiou

Mechanical testing of materials at the microscales is challenging. It requires delicate procedures not only for producing and handling the specimen to be tested, but also for applying an accurate and controlled force. This endeavor is even more challenging ...

MDPI2015

Superhard transparent hybrid nanocomposites for high fidelity UV-nanoimprint lithography

Yves Leterrier, Maïté Blank, Marina Aymara González Lazo

Transparent hyperbranched acrylate nanocomposites were produced using different combinations of silica nanoparticles and silicon-based sol-gel precursors. The nanocomposites were processed using a dual-cure UV polymerization and condensation scheme. The vi ...

2013

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

Low-Stress UV-Curable Hyperbranched Polymer Nanocomposites for High-Precision Devices

Valérie Geiser

The aim of this thesis was to investigate the process-structure-property relationships of UV-curable hyperbranched polymer (HBP)/silica nanocomposites. Special attention was paid to the interplay between photo-conversion, rheological behavior, shrinkage, a ...

EPFL2010

Nanostructured Functional Particles and Surfaces

Arthur Olivier Joseph Ganz

Topographic nanostructuring of surfaces is a promising concept, in particular to improve the bio-integration of titanium orthopedic implants. In this context, a new method for the nanostructuring of anodised titanium surfaces was developed. Ordered topogra ...

EPFL2010

Nanoparticules à noyau métallique recouvert de silice

Heinrich Hofmann, Alke Fink

The invention relates to nanoparticles based on a metal, on a metal alloy or on a metal derivative coated with a silica layer, in which the silica is crystalline silica, in particular crystalline silica in the cristobalite form. They may be prepared from n ...

2006

Nanoindentation and birefringence measurements on fused silica specimen exposed to low-energy femtosecond pulses

Tristan Colomb, Christian Depeursinge, Yves Bellouard

Femtosecond laser pulses used in a regime below the ablation threshold have two noticeable effects on Fused Silica (a-SiO2): they locally increase the material refractive index and modify its HF etching selectivity. The nature of the structural changes ind ...

2006