Comparative mid-IR emission study of holmium doped low-phonon fluoride and chloride crystals

Laser hosts with low maximum phonon energies decrease multiphonon-relaxation (MPR) rates, which enables rare earth emission transitions in the mid-IR region. In this work, a comparative study of mid-IR (3-5 µm) spectroscopic properties on Ho3+ ions doped in various low-phonon fluoride (LaF3, BaF2, NaYF4) and chloride (KPb2Cl5, CsCdCl3, CsPbCl3) based crystals were explored. Experimental results of the mid-IR emission properties using both steady-state and time-resolved fluorescence spectroscopy will be presented. Several laser relevant spectroscopic parameters for the 3.9 µm mid-IR emission of all the studied crystals were determined and compared.