Sensitization of neodymium by chromium and cerium in La1-xNdxMgAl11O19 laser material

Lanthanum-magnesium hexaaluminate LaMg Al11O19 (LNA) with magnetoplumbitelike structure is of considerable interest as a solid-state laser material. Compared to YAG:Nd it presents some advantages, among which are the particular emission wavelengths at 1.054 and 1.082μm tunable over 3.5 and 8.0μm respectively. The hexaaluminate matrix makes possible the substitution of large amounts of Al or Mg by transition metal ions without modifying the crystal growth abilities. This has prompted to investigate the possibilities of sensitizing the neodymium fluorescence in LNA. Such sensitization has led to a dramatic increase of the laser efficiency in the well-known garnet compound GSGG:Nd:Cr. In the lanthanum aluminate, chromium substitutes aluminum preferentially in a distorted octahedral site close to the lanthanide one. Detailed investigations of the Nd3+ fluorescence intensities in LNA and LNA:Cr as well as studies of the fluorescence decay profile of Cr3+ and Nd3+ in the double-doped hexaaluminates indicate that the chromium-neodymium energy transfer is highly efficient in this material