Activation effect of Ho3+ at 2.84 μm MIR luminescence by Yb3+ ions in GGG crystal.

The use of Yb(3+) co-doping for the enhancement of Ho(3+):(5)I(6)→(5)I(7) mid-IR (MIR) emissions was investigated in GGG crystal for the first time. It is established that Yb(3+) highly increases Ho(3+) 2.84 μm emissions by transforming pump energy from the Yb(3+):(2)F(5/2) level to the laser upper level (5)I(6) of Ho(3+). The energy-transfer efficiency from Yb(3+):(2)F(5/2) to Ho(3+):(5)I(6) is calculated to be 96.2%. The absorption cross section, emission cross section, and fluorescence quantum efficiency are estimated and discussed. It is concluded that the Yb, Ho:GGG crystal is promising material for an LD-pumped 2.84 μm laser application.