Evidence of energy transfer among Nd ions in Nd:YAG driven by a mixture of exchange and multipolar interactions

The non-radiative energy transfer between Nd ions in Nd:YAG is investigated through high time-resolution fluorescence measurements of the F-4(3/2) level of Nd. Our experimental data suggests that a strong short-range interaction, i.e., exchange interaction, contributes to the energy transfer process between Nd ions at early times. In addition to it, our Monte Carlo simulations predict a multipolar mixture of interactions, that is, dipole-dipole, dipole-quadrupole, quadrupole-quadrupole and exchange interactions. This result is compared with a similar measurement and analysis for the Nd, Er, Cr:YAG luminescent system previously reported. (C) 1998 Published by Elsevier Science B.V. All rights reserved.