On the 4f25d→4f3 interconfigurational transitions of Nd3+ ions in K2YF5 and LiYF4 crystal hosts

The Laser Induced Fluorescence (LIF) spectrum of K2YF5:Nd3+ (PFYK:Nd) and LiYF4:Nd3+ (YLF:Nd) single crystals, pumped by the fluorine F-2 pulsed discharge molecular laser at 157.6 nm, was obtained in the Vacuum Ultraviolet (VUV) region of the spectrum. The fluorescence peaks were assigned to the 4f(2)5d --> 4f(3) dipole allowed transitions of the Nd3+ ion. The 180 nm band of the LIF spectrum from the crystals indicates that the 4f(2)5d --> 4f(3) dipole transitions originate from the low Stark components of the K-4(11/2) level of the 4f(2)5d configuration. The absorption spectrum of the crystal samples in the VUV was obtained as well and spectroscopic assignment of the levels of the 4f(2)5d configuration was made. The electric crystal field splits all the levels of single and mixed configuration. The energy of the Stark components of the 4f(2)5d configuration in YLF:Nd was shifted by few hundred cm(-1) relative to that of PFYK:Nd. We observed eleven and nine dipole transitions, between the 4I(9/2) ground level of the 4f(3) configuration and the Stark components of the levels of the 4f(2)5d configuration of the Nd3+ ion, in YLF and PFYK crystal hosts, respectively. (C) 1998 Elsevier Science B.V.