VUV emission of rare-earth ions doped into fluoride crystals

VUV emission of LiY1-xErxF4 single crystals (x = 0.05, 0.2, 1) has been stu died in an extended range of excitation energy and in a wide temperature ra nge. It was found that strong concentration quenching occurs in highly dope d crystals leading to nanosecond decay for both spin-allowed and spin-forbi dden 5d-4f transitions in Er3+. The impact mechanism of the energy transfer from the matrix to Er3+ ions results in relatively high quantum yield of E r3+ d-f luminescence in such crystals at high-energy excitation. It was sho wn that the scheme of intermediate electron-phonon coupling should be used for the description of bandwidth temperature broadening for d-f luminescenc e. (C) 2000 Elsevier Science B.V. All rights reserved.