Spectroscopic study of neodymium doped potassium lead bromide for mid-infrared solid state lasers

We present spectroscopic results of the mid-infrared (MIR) emission (I-4(11/2)-> I-4(9/2)) properties of neodymium (Nd) doped potassium lead bromide (KPb2Br5). Following optical excitation at either 0.808 or 0.89 mu m, Nd:KPb2Br5 showed a broad MIR emission band centered at 5.25 mu m with a bandwidth of 0.76 mu m at full width half maximum. For low concentration samples (5 x 10(18) cm(-3)), the emission lifetime was determined to be 43 ms at room temperature and increased to 57 ms at low temperature (15 K). Based on the energy-gap law, non-radiative decay through multi-phonon relaxation is predicted to be negligibly small in this low phonon energy host material with h omega(max) = 138 cm(-1). Therefore, the modest temperature dependence of the MIR lifetime is most likely due to the existence of non-radiative decay related to residual defects in the sample. The peak emission cross-section for the (I11/2 -> I9/2)-I-4-I-4 transition was determined to be 0.65 x 10(-20) cm(2). Some comparative results on Nd:KPb2Cl5 were also included in this study. (c) 2011 Elsevier B.V. All rights reserved.