| 1. |
- Auzel, Francois
(author)
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A condition in Ln-doped materials for flat optical gain
- 2007
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In: Spectroscopy Letters. - : Informa UK Limited. - 0038-7010 .- 1532-2289. ; 40:2, s. 197-207
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Journal article (peer-reviewed)abstract
- Fundamental conditions that rule gain flatness in Er-doped glass optical amplifiers are investigated using few parameters obtained by drastic simplifications for level positions and widths. The obtained general gain flatness condition for rare-earth-doped glasses contains two parts: a general one valid in any material and a slight modulation of it valid only for glasses when "0-0" transitions are involved. Essentially, the electron-phonon coupling for the considered materials has to be larger than 2/3. In order to exemplify these conditions, they are calculated for fluoride and silicate glasses, which are known to display respectively flat and non-flat gain behavior.
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| 2. |
- Auzel, Francois, et al.
(author)
-
Homogeneous line width of rare-earth-doped glasses for levels in a Stark level ladder : A new simple rule
- 2007
-
In: Journal of Luminescence. - : Elsevier BV. - 0022-2313 .- 1872-7883. ; 122:1-2, s. 453-455
-
Journal article (peer-reviewed)abstract
- Concentrating on higher Stark states in multiplet ladders of lanthanide-doped glasses, we show that at 10 K, the homogeneous widths along Stark ladders vary quasi-linearly with the energy position in the ladder.Assuming that the mechanisms creating the homogeneous widths are first-order processes, either direct processes or two-phonon nonradiative transitions, the observed behavior is simply explained by the fact that energy separations between Stark levels for usual glasses are less, i.e., not far from kT(D), the Debye energy. This in turn provides quasi-equal phonon transition probabilities between individual Stark states. A simple theoretical relationship is derived and compared with experiments.
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| 3. |
- Auzel, Francois, et al.
(author)
-
Photon trapping in ruby and lanthanide-doped materials: Recollections and revival
- 2007
-
In: Journal of Luminescence. - : Elsevier BV. - 0022-2313 .- 1872-7883. ; 125:1-2, s. 25-30
-
Journal article (peer-reviewed)abstract
- After some recollections of phonon and photon trapping in ruby, a critical review of this effect of renewed interest in trivalent lanthanide-doped materials is presented showing that the two independent derivations taking their roots in the work of Milne for gases and of Birks for organic scintillators are practically described by an analogous phenomenological equation when re-absorption is weak. The problem of obtaining "extrinsic" quantum efficiency larger than one is briefly discussed.
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