Comment on "Optical Response of Gas-Phase Atoms at Less than lambda/80 from a Dielectric Surface" published by K. A. Whittaker et al.

Comment on "Optical Response of Gas-Phase Atoms at Less than lambda/80 from a Dielectric Surface" published by K. A. Whittaker, J. Keaveney, I. G. Hughes, A. Sargsyan, D. Sarkisyan, C. S. Adams in Phys. Rev. Lett. Lett 112 253201 (2014)Comment: Accepted (dec. 2014) in the "Comment" section of Phys Rev Let

Modeling Commercial Processes and Customer Behaviors to Estimate

We propose a formal model for estimating the diffusion rate of a new product on a coherent market. Our approach is based on a discrete probabilistic modeling of customer behaviors and of commercial processes.Diffusion of innovation, diffusion rate, marketing, customer behavior, product diffusion

A 2D nanosphere array for atomic spectroscopy

We are interested in the spectroscopic behaviour of a gas confined in a micrometric or even nanometric volume. Such a situation could be encountered by the filling-up of a porous medium, such as a photonic crystal, with an atomic gas. Here, we discuss the first step of this program, with the generation and characterization of a self-organized 2D film of nanospheres of silica. We show that an optical characterization by laser light diffraction permits to extract some information on the array structure and represents an interesting complement to electron microscopy.Comment: accept\'e pour publication \`a Annales de Physique- proceedings of COLOQ1

Spectroscopy in Extremely Thin Vapor Cells : Sensitivity Issues

This communication focuses on sensitivity issues - a long-time concern of J. Hall- in the spectroscopic analysis of Extremely Thin Cell of dilute vapor. With these small and often submicrometric slices of vapor, the most uncommon features are the relatively small number of interacting atoms, and the fact that essential results are already obtained in the frame of linear spectroscopy.Comment: Proceedings of the John Hall symposium (2005) to appea

Atom-Wall interaction

This chapter deals with atom-wall interaction occurring in the "long-range" regime (typical distances: 1-1000 nm), when the electromagnetic fluctuations of an isolated atom are modified by the vicinity with a surface. Various regimes of interaction are discussed in an Introductory part, from Cavity Quantum ElectroDynamics modifications of the spontaneous emission, to Casimir effect, with emphasis on the atom-surface van der Waals interaction, characterized as a near-field interaction governed by a z-3 dependence. The major part of the Chapter focuses on the experimental measurements of this van der Waals interaction, reviewing various recent techniques, and insists upon optical techniques, and notably selective reflection spectroscopy which is particularly well-suited when excited atoms are considered. A review of various experiments illustrates the specific effects associated with a resonant coupling between the atomic excitation and surface modes, from van der Waals repulsion to surface-induced resonant transfer, and with anisotropy effects, including metastability transfer induced by a quadrupole contribution in the interaction. The effects of a thermal excitation of the surface -with a possible remote energy transfer to an atom-, and of interaction with nanobodies -which are intrinsically non planar- are notably discussed among the prospects.Comment: \`{a} paraitre dans : Advances in Atomic Molecular and Optical Physics, vol.50, B. Bederson and H. Walther eds., Academic Pres

Resonant infiltration of an opal: reflection lineshape and contribution from in-depth regions

We analyze the resonant variation of the optical reflection on an infiltrated artificial opal made of transparent nanospheres. The resonant infiltration is considered as a perturbation in the frame of a previously described one-dimensional model based upon a stratified effective index. We show that for a thin slice of resonant medium, the resonant response oscillates with the position of this slice. We derive that for adequate conditions of incidence angle, this spatially oscillating behavior matches the geometrical periodicity of the opal, and hence the related density of resonant infiltration. Close to these matching conditions, the resonant response of the global infiltration varies sharply in amplitude and shape with the incidence angle and polarization. The corresponding resonant reflection originates from a rather deep infiltration, up to several wavelengths or layers of spheres. Finally, we discuss the relationship between the present predictions and our previous observations on an opal infiltrated with a resonant vapor.Comment: to appear in J Chem Phy

Modeling Commercial Processes and Customer Behaviors to Estimate

We propose a formal model for estimating the diffusion rate of a new product on a coherent market. Our approach is based on a discrete probabilistic modeling of customer behaviors and of commercial processes

Modeling Commercial Processes and Customer Behaviors to Estimate the Diffusion Rate of New Products

We propose a formal model for describing commercial processes and customer behaviors in order to estimate the diffusion rate of new products among time