High resolution absorption spectroscopy on rare earth doped insulating materials: BaY₂F₈ and YAl₃(BO₃)₄ single crystals and sol‐gel silica glasses

Abstract

The electronic energy transitions occurring in rare earth (RE) ions within the intraconfigurational 4f shell give rise at low temperature to very narrow absorption lines. Even if the shielded 4f shells are weakly coupled with the surrounding, the RE electronic configuration represents a very sensitive probe for the crystal field at the impurity site. Temperature dependent high-resolution absorption measurements can then provide a deep insight into the local crystal field and into the ion interaction with the host lattice. Examples of high resolution Fourier transform spectroscopy measurements performed both on crystalline materials (namely fluoride and borate single crystals) and on sol-gel silica glasses containing nanocrystals are provided and discussed. Correlated analysis based on experimental data and crystal-field calculations is presented.