Evidence for long-range interactions between rare-earth impurity ions in nanocrystals embedded in amorphous matrices with the two-level systems of the matrix - art. no. 100201

The low-temperature homogeneous broadening of the electronic transitions of Eu3+ and Pr3+ rare-earth impurity ions in Y2O3 and LaF3 nanocrystals embed ded into amorphous materials (polymer and oxyfluoride glass ceramics) was s tudied with hole-burning and fluorescence line narrowing techniques. It is- shown that the homogeneous linewidth is determined by the interaction of th e impurity ions contained in the nanocrystals with the two-level systems (T LS's) of the surrounding glass matrix. A comparison of the experiments with a calculation provides direct evidence for the long-range nature of the in teraction with the TLS's.