Spectroscopic investigation and mid-infrared luminescence properties of the Pr3+-doped low phonon single crystals CsCdBr3, KpB2Cl5 and Tl3PbBr5

The low phonon materials KPb2Cl5, CsCdBr3 and Tl3PbBr5 were successfully grown by using the Bridgman-Stockbarger method. These crystals were stable, homogeneous, no moisture sensitive and could be doped with Pr3+ ions. Spectroscopic properties of the 3H5→3H4 Pr3+ transition have been investigated for the three low phonon materials. Absorption and emission cross sections of this transition around 3.8-5.5 μm are broad and present high peak values. Furthermore, gain cross sections derived from these measurements could be positive for small population inversion ratio. Finally, the performance of a continuous wave Pr-doped low phonon single-crystal laser operating on this transition is studied using numerical modelling. By this way it was possible to demonstrate that compact solid-state laser systems could be achieved via quantum-cascade laser (QCL) pumping.