Temperature and concentration dependence of optical dephasing, spectral-hole lifetime, and anisotropic absorption in Eu³+:Y₂SiO₅

Abstract

Detailed site-selective spectroscopy has been performed as a function of temperature on the 7F0↔5D0 transition of Eu3+:Y2SiO5 for Eu3+ concentrations of 0.02%, 0.1%, 0.5%, and 1%. Time-domain optical dephasing, spectral hole lifetimes, anisotropic absorption coefficients, inhomogeneous linewidths, and fluorescence lifetimes for Eu3+ ions at both crystallographic sites were measured. The temperature dependence of the optical dephasing, transition energy, and linewidth of the 7F0→5D0 absorption was measured and interpreted in terms of Raman scattering of phonons. Photon echo measurements of optical dephasing gave T2 values as long as 2.6 ms, approaching the limit set by the fluorescence decay time. Spectral hole lifetimes were measured for temperatures from 2 K to 18 K, with observed lifetimes varying from 1 s at 18 K to an estimated value of greater than 20 days at 2 K. Anisotropic absorption coefficients were measured, and an increase in Eu3+ concentration from 0.02% to 7% produced an increase in the inhomogeneous linewidth Γinh from 0.5 GHz to ∼150 GHz, indicating that Eu3+ doping induces significant strain in the crystal. New determinations of many energy levels of 7FJ multiplets have been made for J=0 to 6. © 2003 The American Physical Society.