Influence of radiation trapping on the characteristics of IR luminescence of YAG:Er³⁺ crystal

The results of spectral and kinetic studies of luminescent radiation parameters at wavelengths near 1500 nm in a YAG:Er3+ crystal under laser excitation at 970 nm are presented. A significant influence of radiation trapping effect on the decay kinetics of luminescent signal on the ⁴I_13/2 → ⁴I_15/2 transition of Er³⁺ ions is revealed. With use of the method of diaphragms with small diameter holes mounted directly in front of the samples, dependences of decay times of recorded luminescent signals on the portion of the trapped radiation were studied. As a lifetime of the first excited level ⁴I_13/2 of Er³⁺ ions in this crystal, the time of luminescence decay from the same level was taken registered with a minimum diaphragm of 100 μm. Under the same conditions the luminescence spectrum of the material under study is recorded which is of interest for 1500 nm generation widely used in optical communications systems