Spectroscopic characterisation of the Tm3+ doped KLa(WO4)2 single crystals

The spectroscopic characterisation of the Tm3+ doped double potassium–lanthanum tungstate KLa(WO4)2 (KLWO) through the absorption, fluorescence and lifetime measurements is presented. We show absorption spectra in the visible and NIR regions recorded at room and low temperature, the luminescence spectra especially that of the 3H4 → 3H6 transition lying in the 800 nm region which makes it suitable for diode laser pumping. The lifetimes were measured for KLa(WO4)2 with 2 at.% of Tm3+ and the values were 112 μs, 208 μs, 1.7 ms and 5.7 μs for 1G4, 3H4, 3F4, and 1D2, respectively. The results of the Judd–Ofelt analysis are presented and discussed. The obtained intensity parameters were used to determine the radiative decay rates, radiative lifetimes and branching ratios for the Tm3+ transitions from the excited multiplet manifolds to the lower lying manifold states. The infrared cross-section measurements were done.