OPTICAL PROPERTIES OF Cr3+ ION IN LaMgAl11O19 and La1-x Ndx MgAl11O19

Lanthanum-magnesium hexaaluminate LaMgAl11O19 with magnetoplumbite-like structure is a remarkable good laser host for Nd3+ ions (LNA). In this study Cr3+ ions are introduced as an activator (LaMgAl11-xCrxO19) or as a sensitizer (La1-xNdxMgAl11O19) in this matrix. ESR and optical spectra of LaMgAl11-xCrxO19 crystals reveal 3 kinds of sites for Cr3+ : (4f), (2a) and (12k). The presence of 4T2 - 4A2 broad band fluorescence makes this material a possible candidate for a red or IR emitting vibronic laser. Optical properties of La1-xNdxMgAl11O19 reveal that both radiative and non-radiative Cr3+ - Nd3+ energy transfers occur in this material. This allows to increase the laser emission ratio compared with single doped LNA