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.