Measurement of local field effects of the host on the lifetimes of embedded emitters.

We report experimental results on the variation of the radiative lifetime of Eu3+ ion embedded in a dielectric with the refractive index n. We dope 1 mol % of Eu3+ into the binary glass system xPbO-(1-x)B2O3. By varying x we have achieved a fairly large variation of the refractive index from 1.7 to 2.2. This enables us to study the local field effects for the first time for ions doped in a solid glassy material. Our measurements are in agreement with the so-called real cavity model. The present measurements are free from the complications arising from reorganizational effects in solvents.