Excess Dephasing in Photon Echo Experiments Arising from Excitation-Induced Electronic Level Shifts.

摘要

Coherent transient optical techniques have been employed with great advantage over the last ten years or so to study the slow optical dephasing of rare-earth and transition-metal impurities in insulators. Working on the 7F(0)-5D(0) transition of Europium (3+) in Yttrium Oxide, we provide the first detailed characterization of excitation-induced shifts in optical transition frequencies and demonstrate their exaggeration of nominally homogeneous dephasing rates. The shifts (found to vary in rough proportion to the number of Eu(3+) ions excited and to be as small as one part in 10 to the 12th power were identified through their unique signature in specially designed photon-echo experiments. The effects reported may constitute a rather general complication in optical measurements of homogeneous relaxation rates in solids. Reprints. (aw)