Relaxation processes of point defects in vitreous silica from femtosecondto nanoseconds

Maurizio Leone, Portuondo-Campa, Callegari, Gawelda, Majed Chergui, Andrea Cannizzo, Van Mourik

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Abstract

We studied ultrafast relaxation of localized excited states at Ge-related oxygen deficient centers insilica using femtosecond transient-absorption spectroscopy. The relaxation dynamics exhibits abiexponential decay, which we ascribe to the departure from the Frank–Condon region of the firstexcited singlet state in 240 fs, followed by cooling in ~10 ps. At later times, a nonexponentialrelaxation spanning up to 40 ns occurs, which is fitted with an inhomogeneous distribution ofnonradiative relaxation rates, following a chi-square distribution with one degree of freedom. Thisreveals several analogies with phenomena such as neutron reactions, quantum dot blinking, orintramolecular vibrational redistribution. © 2008 American Institute of Physics.[DOI: 10.1063/1.2975965]
Lingua originaleEnglish
pagine (da-a)102901_1-102901_3
Numero di pagine3
RivistaApplied Physics Letters
Volume93
Stato di pubblicazionePublished - 2008

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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Leone, M., Portuondo-Campa, Callegari, Gawelda, Chergui, M., Cannizzo, A., & Van Mourik (2008). Relaxation processes of point defects in vitreous silica from femtosecondto nanoseconds. Applied Physics Letters, 93, 102901_1-102901_3.