Phonon generation in condensed 4He by laser-excited atomic bubbles
Department of Physics, University of Fribourg - Chemin du Musée 3, 1700 Fribourg, Switzerland
Accepted: 26 August 2011
We discuss the interaction between nanometer-sized defects (atomic bubbles) and elementary excitations (phonons) in quantum fluids and solids. We observe that optical excitations in embedded metal atoms induce bubble expansions/contractions that create strongly localized phonon wave packets in the quantum matrix. We derive the structure and dynamics of these vibronic excitations from the experimental laser-induced fluorescence spectra of Au and Cu atoms in liquid and solid He. The atomic vibrations are found to be strongly damped on the 50 Å and 5 ps scales in agreement with pure hydrodynamic estimations.
PACS: 67.80.dj – Defects, impurities, and diffusion / 32.70.-n – Intensities and shapes of atomic spectral lines / 63.20.kp – Phonon-defect interactions
© EPLA, 2011