STUDY OF THE CR3-GALLOGERMANATE-TYPE CODOPED CRYSTALS( SENSITIZATION AND STRUCTURAL DISORDER EFFECTS ON THE ND3+ LASER ACTION IN CA)

Energy transfer between Cr3+ and Nd3+ ions in Ca3Ga2Ge4O14 (CGG) and L a3Ga2SiO14 (LGS) crystals has been investigated in the 4.2-300 K tempe rature range by using steady-state and site-selective time-resolved la ser spectroscopy. The transfer efficiency was calculated as a function of temperature by using the Cr3+ lifetimes of the single doped and co -doped samples. Laser experiments were carried out in a diffusive cavi ty by pumping the co-doped rods of CGG and LGS crystals with xenon fla shlamps. The laser spectral emission shows a complex structure which v aries as a function of pump energy. The temporal evolution of the lase r spectrum is discussed in terms of a simple four-level spectral rate- equation laser model by considering the influence of the crystal field disorder on the spectral properties of Nd3+ ions. (C) 1997 Elsevier S cience B.V.