Investigation on growth and spectroscopic properties of Nd3+, Ho3+ co-doped KPb2Cl5 single crystal for laser application

The absorption spectrum, fluorescence spectra, and fluorescence lifetimes were investigated under 808 nm laser diode (LD) excitation. Based on the Judd-Ofelt theory, the radiation properties of Ho3+ ions were thoroughly investigated. The Ωi (i=2,4,6) parameters were fitted as 7.758×10−20, 2.413×10−20, and 0.395×10−20 cm2, respectively. Intense infrared emission bands were observed with the peaks at 2002, 2852.5, and 3910 nm. The fluorescence lifetimes of the 5I7, 5I6, and 5I5 energy levels of Ho3+ ions were determined to be 9.435, 1.640, and 0.810 ms, respectively. The visible upconversion emissions were also observed in the Nd,Ho:KPb2Cl5 crystal excited by 808 nm LD. The energy transfer processes between Nd3+ and Ho3+ ions were discussed in detail. All results demonstrate that the Nd,Ho:KPb2Cl5 crystal has great potential as a gain medium for mid-infrared lasers.