VUV and UV fluorescence and absorption studies of Nd super(3+) and Ho super(3+) ions in LiYF sub(4) single crystals

The laser induced fluorescence spectra of LiYF sub(4):ND super(3+) (YLF:Nd) and LiYF sub(4):Ho super(3+) (YLF:Ho) single crystals, pumped by an F sub(2) pulsed discharge molecular laser at 157 nm were obtained in the vacuum ultraviolet (VUV) and ultraviolet (UV) regions of the spectrum. With this pumping arrangement a number of new fluorescence peaks were observed for the first time. They are assigned to the dipole allowed transitions 4f super(2)5d arrow right 4f super(3) and 4f super(9)5d arrow right 4f super(10) of the Nd super(3+) and Ho super(3+) ions, respectively. The absorption spectra of the same crystal samples in the VUV and UV spectral regions were taken as well.