Temperature dependence of lifetime of 1.3 micron emission from Dy³⁺-doped Ge-As-S glass modified with very small amount of Ga and CsBr

Choi, Y.G., Curry, R.J. and Hewak, D.W. (2012) Temperature dependence of lifetime of 1.3 micron emission from Dy³⁺-doped Ge-As-S glass modified with very small amount of Ga and CsBr. Photoluminescence in Rare Earths: Photonic Materials and Devices (PRE 12), Kyoto, Japan. 27 - 29 Mar 2012.

Abstract

It has been known that the measured lifetime of the 1.3 µm emission from Dy³⁺ ions embedded in sulfur-based chalcogenide glass is dramatically modified upon a least compositional adjustment by Ga+CsBr. For example, greater than ten-fold increase of the measured lifetime is typically observed when less than 1 mol% of Ga+CsBr is introduced to Ge-As-S glass. This novel observation is based on spontaneous atomic rearrangement in the vicinity of Dy³⁺ ions taking place as a result of the compositional modification as well as the hypersensitivity involved in the (⁶H_9/2, ⁶F_11/2) to ⁶H_15/2 transition.
In an effort to get deepened knowledge on the compositional effect, in this study, we have measured the lifetime of 1.3 µm emission as functions of temperature and concentration of Ga+CsBr. As-rich Ge-As-S glasses unmodified or modified with less than 1.0 mol% of Ga+CsBr were prepared, and then decay profiles for the 1.3 µm emission were recorded at various temperatures.
We observe that the measured lifetime, i.e., the first e-folding time, exhibits a very interesting behavior; for modification of up to ~0.4 mol% the lifetime decreases with increasing temperature, as typically observed for multiphonon relaxation dominated transition. However, when concentration of Ga+CsBr reaches ~0.6 mol%, the lifetime keeps almost constant regardless of temperature change. For further increase of the compositional modification up to ~1.0 mol%, the lifetime increases as temperature increases. This novel behavior is discussed in connection with the local structural changes at around Dy³⁺ ions, and the resulting changes in the oscillator strength as well as the center of gravity of the thermally coupled (⁶H_9/2, ⁶F_11/2) manifold.

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Contributors

Author: D.W. Hewak

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