On the 4f 25d→4f 3 interconfigurational transitions of Nd 3+ ions in K 2YF 5 and LiYF 4 crystal hosts

Abstract

The Laser Induced Fluorescence (LIF) spectrum of K 2YF 5:Nd 3+ (PFYK:Nd) and LiYF 4:Nd 3+ (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 25d→4f 3 dipole allowed transitions of the Nd 3+ ion. The 180 nm band of the LIF spectrum from the crystals indicates that the 4f 25d→4f 3 dipole transitions originate from the low Stark components of the 4K 11/2 level of the 4f 25d configuration. The absorption spectrum of the crystal samples in the VUV was obtained as well and spectroscopic assignment of the levels of the 4f 25d 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 25d 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 25d configuration of the Nd 3+ ion, in YLF and PFYK crystal hosts, respectively.