Infrared-excited bright green and red luminescence in La3Ga5.5Ta0.5O14 doped with erbium and ytterbium

Bright green (at 525 and 550 nm) and red (at 660 nm) luminescence in Er:Yb:La3Ga5.5Ta0.5O14 (LGT) powder synthesized by solid state reaction was obtained by pumping at 936 nm. Yb3+-Er3+ energy transfer processes accounting for population of the 2H211/2, 4S3/2 and 4F9/2 Er3+ levels are discussed. The dependence of ratio between the intensities of the green and red luminescence on pump intensity is analyzed. The rather high quantum efficiency (58%) of the (4S3/2, 2H211/2) Er3+ emitting level recommends LGT doped with erbium and ytterbium for upconversion applications.