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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
Yong Gyu Choia, Richard J.Curryb, Dan W.Hewakc
a. Department of Materials Science and Engineering, Korea Aerospace University, Goyang, Gyeonggi 412-791, Republic of Korea
b. Advanced Technology Institute, School of Electronics and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
c. Optoelectronics Research Centre, University of Southampton, UK
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
(6H9/2, 6F11/2) → 6H15/2 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 (6H9/2, 6F11/2) manifold.
PRE '12 Kyoto Japan 28-30 Mar (2012)
Copyright University of Southampton 2006