Optical absorption spectroscopy of Nd3+ in the Ca3Ga2Ge3O12 laser garnet crystal

A systematic investigation of the optical absorption of the Nd3+ ion in the Ca3Ga2Ge3O12:Nd3+ garnet (CCGG:Nd) crystal is presented. An assignment of the Stark energy levels was carried out assuming a D-2 symmetry site for the Nd3+ ions in CGGG:Nd, Some relevant spectroscopy parameters for laser applications: radiative lifetime, branching ratios and quantum efficiency from the F-4(3/2) emitting state were estimated using the Judd-Ofelt theory. (C) 1999 Elsevier Science B.V. All rights reserved

Blue and red photoluminescence from Al2O3 : Ce3+: Mn2+ films deposited by spray pyrolysis

Al2O3:Ce3+:Mn2+ films deposited by the spray pyrolysis technique show blue and red emissions under ultraviolet light excitation. The blue emission is due to the de-excitation of Ce3+ ions from their excited state 5d to the split ground state F-2. The usually weak red emission attributed to 3d -> 3d de-excitation of Mn2+ is enhanced through an efficient energy transfer from Ce3+ to Mn2+ ions. The most probable mechanism of Ce3+ -> Mn2+ energy transfer is found to be electric dipole-quadrupole interaction. The quantum efficiency of this transfer was estimated as being near to 100%, which makes these films interesting phosphors for the design of luminescent layers in flat-panel displays with two-colour emission