Publications de Yves Bellouard

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Under certain exposure conditions, a femtosecond laser beam focused in the bulk of fused silica leads to the formation of self-organized structures consisting of a series of “nanolayers,” parallel to one another. Remarkably, this laser-induced nanoscale an ...

A complete set-up for local annealing of Shape Memory Alloys (SMA) is proposed. Such alloys, when plastically deformed at a given low temperature, have the ability to recover a previously memorised shape simply by heating up to a higher temperature. They find more and more applications in the fields of robotics and micro engineering. There is a tremendous advantage in using local annealing because this process can produce monolithic parts, which have different mechanical behavior at different location of th

Femtosecond laser exposure of fused silica combined with chemical etching has opened up new opportunities for three-dimensional freeform processing of micro-structures that can form complex micro-devices of silica, integrating optical, mechanical and/or fluidic functionalities. Here, we demontrate an expansion of this process with an additional fabrication step that enables the integration of three-dimensional embedded metallic structures out of useful engineering metals such as silver, gold, copper as well

We demonstrate the fabrication of a 3D polymer/glass micromechanical sensor by combining two femtosecond laser direct writing processes: subtractive laser-assisted chemical etching combined with additive two-photon polymerization techniques. In the first s ...

We report on a self-organized process initiated on a potassium-tungsten-tellurite glass surface under repetitive femtosecond laser irradiation in a regime where cumulative effects lead to a localized melting. Specifically, we show that self-organized perio ...

We investigate the use of laser-induced topological transformation for manufacturing multifocal lens arrays with arbitrary focal ranges. Cylindrical preforms manufactured by femtosecond laser and chemical etching are topologically transformed into plano-co ...

Crystallization of amorphous layers has been demonstrated under various radically different laser-exposure conditions, including continuous wave (cw) and pulsed lasers. Here, we investigate the specific role of ionization in the crystallization of dielectr ...

By continuously scanning a femtosecond laser beam across a fused silica specimen, we demonstrate the formation of self-organized bubbles buried in the material. Rather than using high intensity pulses and high numerical aperture to induce explosions in the ...

We report the formation of arbitrary photoconductive patterns made of tellurium (Te) nanocrystals by exposing a tellurite (TeO2-based) glass to femtosecond laser pulses. During this process, Te/TeO2-glass nanocomposite interfaces with photoconductive prope ...

With the advent of ultrafast lasers, new manufacturing techniques have come into existence. In micromachining, the use of femtosecond lasers not only offers the possibility for three-dimensional monolithic fabrication inside a single optically transparent ...

Ultra-Low Expansion (ULE ®) glass, a silica-based glass with TiO 2 content below 10%, possesses the lowest coefficient of thermal expansion among engineered materials and is integral to high-precision optical systems. Despite its technological importance, its interaction with ultrafast laser irradiation remains insufficiently understood. Here, we investigate structural and chemical modifications induced by sub-ablation femtosecond laser pulses in ULE ® glass and assess how Ti incorporation alters energy abs

Microlens Arrays (MLAs) are commonly used in various applications including beam shaping, illumination optics, fiber light coupling and imaging. Here, we investigate unconventional techniques to produce glass MLAs with unique arrangements and different lens properties. We present a laser-assisted manufacturing method combining femtosecond laser machining of preform shapes, wet etching and laser thermal reflow to achieve low surface roughness’s and targeted lens curvatures. This technique has high design fle

Femtosecond pulses used in the regime where self-organized patterns are found have two noticeable effects in amorphous silica's (a-SiO2) optical and chemical properties: The decrease of the material's refractive index as well as an enhanced etching selecti ...

Advanced three-dimensional manufacturing techniques are triggering new paradigms in the way we design and produce sophisticated parts on demand. Yet, to fully unravel its potential, a few limitations have to be overcome, one of them being the realization o ...

Over the last decades, three-dimensional micro-manufacturing of fused silica via near-infrared ultrafast laser exposure combined with an etching step has become an established technique for producing complex three-dimensional components. Here, we explore t ...

Femtosecond laser-dielectric interaction in a three-dimensional (3D) manner defines a capable platform for integrated 3D micro-devices fabricated out of a single piece of system-material. Here, we add a new function to femtosecond laser-based single monoli ...

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 ...

The formation of elemental trigonal tellurium (t-Te) on tellurite glass surfaces exposed to femtosecond laser pulses is discussed. Specifically, the underlying elemental crystallization phenomenon is investigated by altering laser parameters in common tell ...

Among the many complex bioactuators functioning at different scales, the organelle cilium represents a fundamental actuating unit in cellular biology. Producing motions at submicrometer scales, dominated by viscous forces, cilia drive a number of crucial b ...

Controlling the stress in glass after laser exposure is of prime importance not only for photonics applications, but also for preserving the mechanical integrity of glass components in general. The sub-surface exposure of fused silica to femtosecond laser ...

Yves Bellouard

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Elastic properties of self-organized nanogratings produced by femtosecond laser exposure of fused silica

Local annealing of shape memory alloys using laser scanning and computer vision

Femtosecond laser assisted 3-dimensional freeform fabrication of metal microstructures in fused silica

Hybrid laser 3D microprocessing in glass/polymer micromechanical sensor: towards chemical sensing applications

Direct-write laser-induced self-organization and metallization beyond the focal volume in tellurite glass

Glass multifocal microlens array through laser-induced topological transformation

Influence of ionization and cumulative effects on laser-induced crystallization in multilayer dielectrics

Femtosecond-laser generation of self-organized bubble patterns in fused silica

Femtosecond-laser direct-write photoconductive patterns on tellurite glass

A Monolithic Gimbal Micro-Mirror Fabricated and Remotely Tuned with a Femtosecond Laser

Femtosecond laser interaction with ULE® glass

3D manufacturing of glass multifocal microlens-arrays and skewed optics through laser assisted processes

Investigation of the micro-mechanical properties of femtosecond laser-induced phases in amorphous silica

Few pulses femtosecond laser exposure for high efficiency 3D glass micromachining

High-efficiency non-ablative UV laser nano-scale processing of fused silica by stable filamentation

Progress on femtosecond laser-based system-materials: three-dimensional monolithic electrostatic micro-actuator for optomechanics

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

Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation

Highly motile nanoscale magnetic artificial cilia

Stress-state manipulation in fused silica via femtosecond laser irradiation