Polarized optical spectra of Ho3+-doped KPb2Cl5 single-crystal

The polarized absorption and emission spectra of a KPb2Cl5 (KPC) crystal activated with Ho3+ ions have been measured in the 400-4000 nm region. The absorption spectra have been analyzed in the framework of the Judd-Ofelt Theory and the results have been compared with those, contradictory, reported in literature. The emission measurements in near and mid infrared confirm the attractiveness of this material for 2, 3 and 4 μm laser applications, thanks to the very low phonon cut-off (203 cm−1) of the host lattice.