• Hewak, Daniel W.
• Craig, Christopher
• Kasap, Safa
• Koughia, Cyril

Abstract

Absorption and emission bands in trivalent erbium ions Er3+ are known to strongly overlap, which means that in heavily doped samples, it is possible to observe the effects of sequential radiation absorption and re-emission processes that involve the Er3+ ions. In particular, this effect of “radiation trapping” (RT) or “radiation/ excitation diffusion” is responsible for the dependence of the measured photoluminescence (PL) lifetime and PL spectrum shape in Er3+ chalcogenide glasses on the rare-earth doping concentration and sample size.[1,2]. It is worth mentioning here that the original name “excitation diffusion” originates from Milne’s paper where he pointed out the formal similarity of equations describing the effect with those for normal diffusion [3].In present paper we present the results of experiments which are design to maximize the effect of RT by passing the light along the bulk of a chalcogenide glass sample as shown in Figure 1 (b-d). We carry out experiments on samples having regular cylindrical shape, which allows us to do some simple calculations predicting the shape and lifetime of PL (see Equations (1-3) in Figure 1). The results of these predictions appear to be in a very good agreement with experimental data as shown in Figure 1(a). These results show that RT effectively “stirs” the excitation inside of sample, evenly distributing it throughout the whole volume of the sample.&more...

Topics

• impedance spectroscopy
• photoluminescence
• experiment
• glass
• glass
• Erbium