Luminescence spectrosopy of Ei(III) in lanthanum magnesium aluminate, a solid state laser host

Note:Laser induced luminescence of Eu(lll) in La 1-x Eu x MgAl11O19 (LMA) was studied for three different concentrations (x-0.1, 0.01 and <0.01) at various temperatures between SK and 300K. The polarization of this luminescence was investigated in the highest concentration sample. Results show that Eu(lll) occupies three distinct substitutional sites associated respectively with: the Beevers-Ross position (BR, D3h), the mid-Oxygen position (mO, C2v) and a third "intermediate energy" position. The BR site was identified for the first time in these samples. Luminescence peaks of the 50~7F0,1 were assigned for the first time and the orientation of the principal axis of the three sites with rasped to c was determined. Excitation spectra recorded at low temperature for the three concentrations show that Eu(lll) is forced into the BR site as its concentration increases. An analysis of the phenomenological crystal-field parameters suggests that the "intermediate energy site" is mid-way between the BR and the mO sites.Laser induced luminescence of Eu(lll) in La 1-x Eu x MgAl11O19 (LMA) was studied for three different concentrations (x-0.1, 0.01 and