2 μm emission of PbF2 single crystal co-doped with Ho3+/Yb3+ ions

Single crystal of Ho3+/Yb3+ co-doped PbF2 has been grown successfully by the conventional technique modified Bridgman method. The spectral parameters of Ho3+ were calculated based on the Judd-Ofelt theory. The transition probabilities, radiative lifetime, and branching ratios were also estimated in detail by the J-O parameters obtained. The 2 μm emission characteristic and fluorescence lifetime of the 5I7 manifold upon excitation of a conventional 970 nm laser diode were measured and investigated. Fuchtbauer-Ladenburg theory was applied to calculate the absorption, emission, and gain cross sections of 5I7→5I8 transition. Based on examination of spectroscopic parameters evaluated, we suggest Ho3+/Yb3+ co-doped PbF2 crystal is a promising candidate for efficient 2 μm laser.