12 results match your criteria: "Institute of Optics Graduate School[Affiliation]"

Scalable spin squeezing in a dipolar Rydberg atom array.

Nature

September 2023

Charles Fabry Laboratory University of Paris-Saclay, Institute of Optics Graduate School, CNRS, Palaiseau Cedex, France.

The standard quantum limit bounds the precision of measurements that can be achieved by ensembles of uncorrelated particles. Fundamentally, this limit arises from the non-commuting nature of quantum mechanics, leading to the presence of fluctuations often referred to as quantum projection noise. Quantum metrology relies on the use of non-classical states of many-body systems to enhance the precision of measurements beyond the standard quantum limit.

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Continuous symmetry breaking in a two-dimensional Rydberg array.

Nature

April 2023

Institute of Optics Graduate School, CNRS, Charles Fabry Laboratory, University of Paris-Saclay, Palaiseau Cedex, France.

Spontaneous symmetry breaking underlies much of our classification of phases of matter and their associated transitions. The nature of the underlying symmetry being broken determines many of the qualitative properties of the phase; this is illustrated by the case of discrete versus continuous symmetry breaking. Indeed, in contrast to the discrete case, the breaking of a continuous symmetry leads to the emergence of gapless Goldstone modes controlling, for instance, the thermodynamic stability of the ordered phase.

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High-Density Nanowells Formation in Ultrafast Laser-Irradiated Thin Film Metallic Glass.

Nanomicro Lett

April 2022

Univ Lyon, UJM-Saint-Etienne, CNRS, Institute of Optics Graduate School, Laboratoire Hubert Curien, UMR CNRS 5516, 42023, St-Etienne, France.

We present an effective approach for fabricating nanowell arrays in a one-step laser process with promising applications for the storage and detection of chemical or biological elements. Biocompatible thin films of metallic glasses are manufactured with a selected composition of ZrCu, known to exhibit remarkable mechanical properties and glass forming ability. Dense nanowell arrays spontaneously form in the ultrafast laser irradiation spot with dimensions down to 20 nm.

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Ultraviolet radiation as a germicide is widely used in the health field and even in domestic hygiene. Here, we propose an improvement in low-cost portable units of filtration for indoor air, which is based on ultraviolet radiation. In the current technology, to carry out an air filtration with a suspension of aerosols in which there is a likely concentration of pathogens, whether viral, bacterial or molds, the air is forced to pass as close as possible to the ionizing radiation source (near field).

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Multiple studies have reported the observation of electro-synaptic response in different metal/insulator/metal devices. However, most of them analyzed large (>1 µm ) devices that do not meet the integration density required by industry (10  devices/mm ). Some studies emploied a scanning tunneling microscope (STM) to explore nano-synaptic response in different materials, but in this setup there is a nanogap between the insulator and one of the metallic electrodes (i.

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On the Thermal Models for Resistive Random Access Memory Circuit Simulation.

Nanomaterials (Basel)

May 2021

Electrical Engineering and Computer Science Department, University of California, Berkeley, CA 94720-1770, USA.

Resistive Random Access Memories (RRAMs) are based on resistive switching (RS) operation and exhibit a set of technological features that make them ideal candidates for applications related to non-volatile memories, neuromorphic computing and hardware cryptography. For the full industrial development of these devices different simulation tools and compact models are needed in order to allow computer-aided design, both at the device and circuit levels. Most of the different RRAM models presented so far in the literature deal with temperature effects since the physical mechanisms behind RS are thermally activated; therefore, an exhaustive description of these effects is essential.

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Self-Organization Regimes Induced by Ultrafast Laser on Surfaces in the Tens of Nanometer Scales.

Nanomaterials (Basel)

April 2021

UJM-St-Etienne, CNRS, Laboratoire Hubert Curien UMR 5516, Institute of Optics Graduate School, Univ Lyon, F-42023 Saint-Etienne, France.

A laser-irradiated surface is the paradigm of a self-organizing system, as coherent, aligned, chaotic, and complex patterns emerge at the microscale and even the nanoscale. A spectacular manifestation of dissipative structures consists of different types of randomly and periodically distributed nanostructures that arise from a homogeneous metal surface. The noninstantaneous response of the material reorganizes local surface topography down to tens of nanometers scale modifying long-range surface morphology on the impact scale.

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Article Synopsis
  • Femtosecond laser treatment is a powerful tool for altering surface structures, enhancing the functionalities of materials like thin-film metallic glasses, which have unique properties free from typical defects.
  • ZrCu alloys' response to ultrafast laser pulses reveals that their initial microstructure significantly influences how their surface topography changes and the energy needed for nanoscale modifications.
  • Using double pulse femtosecond laser irradiation can effectively produce uniform nanostructures in materials that usually struggle to form them due to unfavorable thermomechanical characteristics.
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On the Insignificant Role of the Oxidation Process on Ultrafast High-Spatial-Frequency LIPSS Formation on Tungsten.

Nanomaterials (Basel)

April 2021

UJM-Saint-Etienne, CNRS, Laboratoire Hubert Curien UMR 5516, Institute of Optics Graduate School, University Lyon, F-42023 St-Etienne, France.

Article Synopsis
  • The study investigates how the presence of surface oxides and different laser texturing environments affect the formation of high-spatial-frequency laser-induced periodic surface structures (HSFLs) on tungsten.
  • Experiments involved using a femtosecond laser under various atmospheres (ambient air, nitrogen, argon, and vacuum) while also removing native oxide layers via plasma sputtering.
  • Findings indicate that oxygen has little impact on HSFL formation, while ambient pressure significantly influences the periodicity of the resulting structures, achieving sub-100 nm periodicity and sub-20 nm amplitude.
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Non-Diffractive Bessel Beams for Ultrafast Laser Scanning Platform and Proof-Of-Concept Side-Wall Polishing of Additively Manufactured Parts.

Micromachines (Basel)

October 2020

Laboratoire Hubert Curien, UMR 5516 CNRS, Institute of Optics Graduate School, Université de Lyon, Université Jean Monnet, 42000 Saint-Etienne, France.

We report the potential use of non-diffractive Bessel beam for ultrafast laser processing in additive manufacturing environments, its integration into a fast scanning platform, and proof-of-concept side-wall polishing of stainless steel-based additively fabricated parts. We demonstrate two key advantages of the zeroth-order Bessel beam: the significantly long non-diffractive length for large tolerance of sample positioning and the unique self-reconstruction property for un-disrupted beam access, despite the obstruction of metallic powders in the additive manufacturing environment. The integration of Bessel beam scanning platform is constructed by finely adapting the Bessel beam into a Galvano scanner.

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Sub-100 nm 2D nanopatterning on a large scale by ultrafast laser energy regulation.

Nanoscale

March 2020

Univ Lyon, UJM-Saint-Etienne, CNRS, Institute of Optics Graduate School, Laboratoire Hubert Curien UMR CNRS 5516, F-42023 St-Etienne, France.

Coupling ultrafast light irradiation to surface nanoreliefs leads to periodic patterns, achieving record processing scales down to tens of nanometers. Driven by near-field interactions, the promising potential of the spontaneous pattern formation relies on the scaling up of one-step manufacturing processes. Here, we report the self-assembly of unconventional arrays of nanocavities of 20 nm diameter with a periodicity down to 60 nm upon ultrafast laser irradiation of a nickel surface.

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Nonequilibrium optical properties of transition metals upon ultrafast electron heating.

J Phys Condens Matter

September 2018

Univ Lyon, UJM-St-Etienne, CNRS, Institute of Optics Graduate School, Laboratoire Hubert Curien UMR 5516, F-42023 Saint-Etienne, France.

Femtosecond laser excitation of metals triggers swift modifications of the electronic distribution within the band structure. This has direct consequences on optical transitions transiently modifying the optical properties of materials. Influencing in real time the action of the pulse, these changes lead to substantial variations of the amount and the distribution in the energy deposited during the laser irradiation.

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