HAL Portal IOGS (nstitut d'Optique Graduate School)
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Effect of Rare-Earth Co-Doping on the Trap Level Concentrations in Silica Glasses: Experimental and Theoretical Study of the Light Emission Under X-Rays for Dosimetry Applications
No full textInternational audienceIn this paper, an experimental and theoretical study was undertaken to assess the impact of rare-earth co-doping of silica glasses on the light emission under X-rays. To this aim, radioluminescence (RL), phosphorescence (PP), and thermoluminescence (TL) signals of Ce3+/Gd3+ co-doped silica glasses have been successively measured and combined at different dose rates and irradiation temperatures. The RL response of the weakly co-doped sample was found to be temperature-independent between 273 K and 353 K. This result suggests that, based on this RL response, it is possible to design ionizing radiation sensors independent of the irradiation temperature in the corresponding range. Moreover, a model that considers the electron–hole pair generation, the charge carrier trapping–detrapping, and the electron–hole recombination in the localized and delocalized bands has been developed to reproduce these optical signals. The theoretical model also explains the temperature independence of the RL response between 273 K and 353 K for the weakly co-doped sample and, therefore, the operating principle of an X-ray sensor independent of the irradiation temperature
Complete retrieval of attosecond photoelectron dynamics from partially coherent states in entangled photoemission
No full textInternational audienceWe show that the complete photoemission dynamics in situations of electron-ion entanglement can be retrieved from photoelectron spectral measurements without information on the ion. To this end, we develop an energy-time analysis of the photoelectron's reduced density matrix based on first principles. We test and assess our approach with numerical simulations on a low-dimensional model molecule in interaction with broadband composite pulses concealing the vibrational resolution. Our method is directly applicable to recent experimental schemes measuring the photoelectron reduced density matrices in atomic and molecular photoemission. Therefore, it opens a new window on the dynamics of decoherence and entanglement at the attosecond timescale
Terrestrial Very-Long-Baseline Atom Interferometry: summary of the second workshop
No full textInternational audienceThis summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024 (Second Terrestrial Very-Long-Baseline Atom Interferometry Workshop, Imperial College, April 2024), building on the initial discussions during the inaugural workshop held at CERN in March 2023 (First Terrestrial Very-Long-Baseline Atom Interferometry Workshop, CERN, March 2023). Like the summary of the first workshop (Abend et al. in AVS Quantum Sci. 6:024701, 2024), this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions (Memorandum of Understanding for the Terrestrial Very Long Baseline Atom Interferometer Study)
High sensitivity Grating-SPR based sensor using Low-Loss Surface Plasmon modes coupling for the detection of H2
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Temperature Impact on a Radioluminescent Silica-based Optical Fiber Dosimeter for Space Applications
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A simple magnetic field stabilization technique for atomic Bose-Einstein condensate experiments
No full textInternational audienceWe demonstrate a simple magnetic field stabilization technique in a Bose-Einstein condensate experiment. Our technique is based on the precise measurement of the current fluctuations in the main magnetic field coils and amounts to their compensation using an auxiliary coil. It has the advantage of simplicity as compensation is done using a low inductance coil that can be straightforwardly driven at the relevant frequencies (1 kHz). The performances of the different components (power supply, current transducer, electronics...) are precisely characterized. In addition, for optimal stability the ambient magnetic field is also measured and compensated. The magnetic field stability around 57 G is measured by Ramsey spectroscopy of magnetic field sensitive radiofrequency transition between two spin states of potassium 39 and the shot-to-shot fluctuations are reduced to 64(7) µG rms, i.e. at the 1 × 10 -6 level. In the context of our experiment, this result opens interesting prospects for the study of three-body interactions in Bose-Einstein condensate potassium spin mixtures
Experimental Protocol for Color Difference Evaluation Under Stabilized LED Light
No full textInternational audienceThere are two key factors to consider before implementing a color discrimination experiment. First, a set of color patches should be selected or designed for the specific purpose of the experiment to be carried out. Second, the lighting conditions should be controlled to eliminate the impact of lighting instability on the experiment. This paper addresses both of these challenges. It proposes a method to print pairs of color patches with non-noticeable color differences. It also proposes a method to stabilize the Spectral Power Distributions (SPDs) of a Light-Emitting Diode (LED) lighting system. Finally, it introduces an experimental protocol for a color discrimination study that will be performed thanks to the contributions presented in this paper
Enhanced generation of optical rogue waves through higher-order saturable absorption in noise-like pulse fiber lasers
No full textInternational audienceWe investigate the self-generation of optical rogue waves from a noise-like pulse (NLP) fiber laser using the nonlinear polarization evolution mechanism as a virtual saturable absorber. We demonstrate a significant enhancement of the rate of rogue wave generation when a higher-order saturable absorption nonlinearity is selected. Numerical simulations and theoretical analysis corroborate and elucidate the experimental observations, showing that a higher probability for the optical rogue wave generation is achieved by combining overdriven saturated absorption with NLP generation