HAL Portal IOGS (nstitut d'Optique Graduate School)
Not a member yet
12589 research outputs found
Sort by
Estimation of scattering properties modifications caused by in vivo human skin optical clearing using line‐field confocal optical coherence tomography
No full textInternational audienceThe image contrast and probing depth of optical methods applied to in vivo skin could be improved by reducing skin scattering using the optical clearing method. The aim of this study was to quantify, from line‐field confocal optical coherence tomography (LC‐OCT) 3D images, the modifications of skin scattering properties in vivo during optical clearing. Nine mixtures of optical clearing agents were used in combination with physical and chemical permeation enhancers on the human skin of three healthy volunteers. Scattering coefficient and anisotropy factor of the epidermis and the upper dermis were estimated from the 3D LC‐OCT images of skin using an exponential decay model of the in‐depth intensity profile. We were able to demonstrate a decrease in epidermal scattering (down to 33%) related to optical clearing, with the best results obtained by a mixture of polyethylene glycol, oleic acid, and propylene glycol
Photo-patterned plasmonic multilayers exhibiting different vivid colors in specular and diffuse reflection
No full textInternational audienc
Differential graded algebras with divided powers and homotopy Lie algebras
No full textGiven a commutative ring R and a quotient module R/m, we study the structure of differential graded algebra with divided powers that the resolution of R/m can possess. We provide a construction of such a resolution by making use of symmetric tensors, which does not require a Noetherian assumption on R. We then apply those results to study the homotopy Lie algebra associated to a the pair (R, R/m), and then investigate in more details the complete intersection case
Optimization strategy of ultra-compact metasurface-based filter ordering on sensors for improved spectral retrieval
No full textInternational audienc
Quantifying Two-Mode Entanglement of Bosonic Gaussian States from Their Full Counting Statistics
No full textInternational audienceWe study the entanglement properties of two-mode bosonic Gaussian states based on their multi-mode counting statistics. We exploit the idea that measuring high-order correlations of particle numbers can reveal entanglement without making any assumptions about the coherence of the fields. We show that the two- and four-body number correlations are sufficient to fully characterize the entanglement of two-mode bosonic Gaussian states for which each mode exhibits a thermal distribution. In addition, we derive an entanglement witness based on two-body correlations alone. Our findings are of great importance because it becomes possible to reveal entanglement in a series of recent experiments
Hetero‐Functionalization of Carbon Nanotubes Termini with Single‐Molecule Control
No full textInternational audienceAbstract A strategy is presented for the asymmetric chemical functionalization of individual single‐walled carbon nanotubes (SWCNTs) termini and their selective conjugation to distinct single moieties, i.e., the formation of bi‐functionalized R‐CNT‐R’ heterostructures. This study demonstrates this via the selective covalent attachment of metal nanoparticles (NPs) and semiconductor nanocrystals (quantum dots, QDs) at opposite ends of individual SWCNTs; the electronic coupling is further characterized between the distinct components of the hybrids. The general applicability of the methodology developed by this study can be beneficial for the design and development of novel SWCNT‐based nanohybrid materials with single‐molecule control
Probing spin-motion coupling of two Rydberg atoms by a Stern-Gerlach-like experiment
No full textInternational audienceWe propose and implement a protocol to measure the state-dependent motion of Rydberg atoms induced by dipole-dipole interactions. Our setup enables simultaneous readout of both the atomic internal state and position on a one-dimensional array of optical tweezers. We benchmark the protocol using two atoms in the same Rydberg state, which experience van der Waals repulsion, and measure velocities in agreement with theoretical predictions. When preparing the atoms in a different pair state, we observe an oscillatory dynamics that we attribute to the proximity of a macrodimer bound state. Finally, we perform a Stern-Gerlach-like experiment in which a superposition of the two previous pair states results in the separation of the atomic wave packet into two macroscopically distinct trajectories, thereby demonstrating spin-motion coupling mediated by the interactions
Review of plasma etching processes for III-V semiconductors
No full textInternational audienceThis paper provides a comprehensive literature review and analysis of III-V semiconductor plasma etching, highlighting key etching considerations and providing literature references to inform future process development. Plasma etching processes for III-V materials such as gallium arsenide (GaAs), indium phosphide (InP), and gallium nitride (GaN) are essential to fabricate many photonic and optoelectronic devices. Such applications frequently require etches with high anisotropy, selectivity and aspect ratio while maintaining minimal roughness and lateral etching. Ten plasma etching techniques used for III-V materials as well as the impact of plasma process parameters on etch results are reviewed. Main etching challenges include aluminum oxidation, non-volatile indium etch subproducts when <150 • C, and strong III-N bonds. Exhaustive reference tables are generated to report capacitively coupled plasma (CCP) and inductively coupled plasma (ICP) etching process parameters for the main binary, ternary, and quaternary III-V semiconductors. An analysis of binary III-V etching is presented in a summative reference plot, which highlights trends in etch rate, etch technology, and active gas chemistry. Among studies reporting etch rates, gallium arsenide was etched most frequently, with ICP being the dominant etch technique. Multilayer systems and plasma damage are briey discussed, with postetch treatments and hydrogen plasmas being used for damage passivation. Overall, III-V materials can be etched with plasma up to several µm/min, with most processes using chlorine-based chemistries such as Cl 2 , BCl 3 , and SiCl 4 . 6 Material-based etching eects 25 6.1 Sample carrier eects . . . . .</div
Increasing the spatial bandwidth product in light field microscopy with remote scanning
No full textInternational audienceAchieving fast, large-scale volumetric imaging with micrometer resolution has been a persistent challenge in biological microscopy. To address this challenge, we report an augmented version of light field microscopy, incorporating a motorized tilting mirror upstream of the camera. Depending on the scanning pattern, the field of view and/or the lateral resolution can be greatly improved. Our microscope technique is simple, versatile, and configured for bright-field and epifluorescence modes. We demonstrate its performance with imaging of multi-cellular aggregates of various shapes and sizes
Connected correlations in cold atom experiments
No full textInternational audienceThe recent development of single-atom-resolved probes has made full counting statistics measurements accessible in quantum gas experiments. This capability provides access to high-order moments of physical observables, from which cumulants, or equivalently connected correlations, can be precisely determined. Through a selection of recent cold atom experiments, this article illustrates the significance of connected correlations in characterizing ensembles of interacting quantum particles. First, non-zero connected correlations of order n > 2 unambiguously identify non-Gaussian quantum states. Second, connected correlations of order n identify clusters made of n elements whose statistical properties are irreducible to combinations of smaller clusters. The ability to identify such multi-particle clusters offers a an interesting perspective on strongly correlated quantum states of matter at the microscopic scale