Energy level decay processes in Ho3-doped tellurite glass relevant to the 3 μm transition

Laércio Gomes, Daniel Milanese, Joris Lousteau, Nadia Boetti, Stuart D. Jackson

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18 Citations (Scopus)

Abstract

The primary excited state decay processes relating to the5I65I7∼ 2.9 m laser transition in singly Ho3-doped tellurite (TZBG) glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the5I6energy level at 1151 nm and5I7energy level at 1958 nm has established that the rate of energy transfer up-conversion between holmium ions excited to the5I7level is negligible for Ho3concentrations up to 4 mol. Excited state absorption was not observed from either the5I7or5I6levels and the luminescence from the5I7and5I6energy levels was measured to peak at ∼2050 nm and ∼2930 nm, respectively. The5I6level has a low luminescence efficiency of ∼8.9 due to strong nonradiative multiphonon relaxation. In contrast, decay from the5I7level is essentially fully radiative. A linear decrease in the decay time of the5I6level with Ho3concentration augmentation results from energy transfer to OH-ions in the glass (with NOH∼ 8.2 1017ions cm-3) and reduces the luminescence efficiency of the5I6level to 8 for [Ho3] 4 mol. Numerical simulation of a fiber laser incorporating 4 mol. Ho3showed that a population inversion of ∼7.8 is reached for square pulses of 100 s duration and a repetition frequency of 20 Hz at a moderate pump intensity of 418 kW cm-2if energy transfer to OH-radicals is neglected.

Original languageEnglish
Article number103110
Pages (from-to)1-6
Number of pages6
JournalJournal of Applied Physics
Volume109
Issue number10
DOIs
Publication statusPublished - 15 May 2011
Externally publishedYes

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