Site-selective fluorescence spectroscopy of Eu3+ and Sm2+ ions in glass

Fluorescence line-narrowing or site-selective fluorescence experiments on Eu3+ and Sm2+ ions in glass are reviewed. It is shown that this technique gives detailed information that is difficult to obtain by other means, such as site-dependent homogeneous widths, inhomogeneous broadening mechanisms, distribution of crystal-field components in glass, and so on. A simple theoretical treatment to consider only the second-order terms of the crystal-field potential is discussed and is shown to be very effective. It will be emphasized that J-mixing, i.e., wave function mixing between 4fN states through the static crystal-field potential, plays a significant role in the optical properties of rare-earth ions in glass