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  • Evidence of different red e...
    Alessi, A.; Di Francesca, D.; Agnello, S.; Girard, S.; Cannas, M.; Richard, N.; Boukenter, A.; Ouerdane, Y.

    Journal of luminescence, 09/2016, Letnik: 177
    Journal Article

    This experimental investigation is focused on a radiation induced red emission in Ge doped silica materials, elaborated with different methods and processes. The differently irradiated samples as well as the pristine ones were analyzed with various spectroscopic techniques, such as confocal microscopy luminescence (CML), time resolved luminescence (TRL), photoluminescence excitation (PLE) and electron paramagnetic resonance (EPR). Our data prove that irradiation induces a red luminescence related to the presence of the Ge atoms. Such emission features a photoexcitation spectrum in the UV-blue spectral range and, TRL measurements show that its decrease differs from a single exponential law with a lifetime of tens of nanoseconds. CML measurements under laser at 633nm evidenced the lack of correlation of the emission here reported with that of the Ge- or Si- non bridging oxygen hole centers. Moreover, our EPR experiments highlighted the lack of correlation between the red emitting defect with other radiation induced paramagnetic centers such as the E′Ge and Ge(2). The relation of the investigated emission with the H(II) defects, previously considered as responsible for a red emission, can not be totally excluded. •Composite nature of the red emission in Ge-doped doped silica materials.•Experimental study with various spectroscopic techniques and on different samples.•Time resolved and stationary characterization of an new red emission.•Study of the spatial distributions of diverse red emissions in optical fibers.