title: Casimir-Polder interactions in the presence of thermally excited surface modes.
abstract: The temperature dependence of the Casimir-Polder interaction addresses fundamental issues for understanding vacuum and thermal fluctuations. It is highly sensitive to surface waves, which, in the near field, govern the thermal emission of a hot surface. Here we use optical reflection spectroscopy to monitor the atom-surface interaction potential between a Cs*(7D3/2) atom and a hot sapphire surface at distances of ~100 nm. In our experiments, that explore a large range of temperatures (500-1,000 K), the surface is at thermal equilibrium with the vacuum. The observed increase of the interaction with temperature, by up to 50%, relies on the coupling between atomic virtual transitions in the infrared range and thermally excited surface-polariton modes. We extrapolate our findings to a broad distance range, from the isolated atom to the short distances relevant to physical chemistry. Our work also opens the prospect of controlling atom-surface interactions by engineering thermal fields.
authors.affiliation: 1] Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris-Cité, F-93430, Villetaneuse, France [2] CNRS, UMR 7538, LPL, 99 Avenue J.-B. Clément, F-93430 Villetaneuse, France.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Laliotis
authors.affiliation: 1] Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris-Cité, F-93430, Villetaneuse, France [2] CNRS, UMR 7538, LPL, 99 Avenue J.-B. Clément, F-93430 Villetaneuse, France [3] Laboratório de Superfície, DF-CCEN, Cx. Postal 5086 Universidade Federal de Paraíba, 58051-900 João Pessoa, Paraíba, Brazil.
authors.forename: Thierry
authors.initials: T
authors.lastname: Passerat de Silans
authors.affiliation: 1] Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris-Cité, F-93430, Villetaneuse, France [2] CNRS, UMR 7538, LPL, 99 Avenue J.-B. Clément, F-93430 Villetaneuse, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Maurin
authors.affiliation: 1] Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris-Cité, F-93430, Villetaneuse, France [2] CNRS, UMR 7538, LPL, 99 Avenue J.-B. Clément, F-93430 Villetaneuse, France.
authors.forename: Martial
authors.initials: M
authors.lastname: Ducloy
authors.affiliation: 1] Laboratoire de Physique des Lasers, Université Paris 13, Sorbonne Paris-Cité, F-93430, Villetaneuse, France [2] CNRS, UMR 7538, LPL, 99 Avenue J.-B. Clément, F-93430 Villetaneuse, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bloch