Excited state dynamics in Ho:KPb2Cl5

Abstract Optical absorption spectra, emission spectra, and fluorescence lifetimes were measured for a number of visible and infrared transitions in Ho 3+ doped KPb 2 Cl 5 . Judd–Ofelt parameters were obtained by using the conventional approach, as well as by a modified approach that minimizes the fractional difference, rather than the absolute difference, between calculated and measured oscillator strengths. Both procedures gave good overall agreement between measured and calculated lifetimes, with an average difference of ≈15%. This confirms the expectation from the multiphonon energy gap law that most observed transitions in Ho 3+ :KPb 2 Cl 5 are highly radiative. Emission cross section spectra for the transitions 5 F 3  →  5 I 8 , 5 G 5  →  5 I 7 , 5 F 3  →  5 I 7 , 5 F 4 / 5 S 2  →  5 I 7 , and 5 I 7 →  5 I 8 were obtained from measured emission spectra, with the peak cross section values scaled by the Judd–Ofelt calculated oscillator strengths.