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Q: Fachverband Quantenoptik und Photonik

Q 10: Quantum Optics and Nuclear Quantum Optics I

Q 10.2: Talk

Monday, March 10, 2025, 17:30–17:45, AP-HS

Two-photon excitation spectroscopy of high pressure xenon-noble gas mixtures — •Eric Boltersdorf, Thilo vom Hövel, Frank Vewinger und Martin Weitz — Institut für Angewandte Physik, Bonn, Deutschland

Photons confined in a dye-filled optical microcavity can exhibit Bose-Einstein condensation upon thermalization through repeated absorption and (re-)emission processes on the dye molecules. This has been experimentally demonstrated for photons in the visible spectral regime in 2010. In the present work, an experimental approach is investigated to realize Bose-Einstein condensation of vacuum-ultraviolet (100nm-200nm; VUV) photons via repeated absorption and (re-)emission cycles between the 5p⁶ ground state and the 5p⁵6s (J = 1) excited state of xenon-noble gas excimer molecules in dense gaseous ensembles (pressure of up to 100 bar). The optical pumping via two-photon excitation from xenon’s 5p⁶ electronic ground-state to higher lying states, e.g. the 5p⁵6p and 5p⁵6p’ states, is investigated. We report on the measurement of excitation spectra with excitations wavelengths ranging from 220 nm to 260 nm. The emission is collected between 145nm and 180nm, which stems from the decay of the 5p⁵6s (J = 1) state that was proposedly populated by collisional deactivation from the higher lying excited states. Data will be shown for xenon-helium mixtures as well as for xenon-krypton mixtures, showing strong dependency on pressure and the atomic species.

Keywords: Bose-Einstein Condensation; Photon Gas; Spectroscopy; Vacuum-Ultraviolet; Two-Photon Excitation