SENSITIZATION OF THE LUMINESCENCE OF ER3+ AND HO3+ IONS BY CR4+ IONS IN A Y2SIO5 CRYSTAL

The luminescence of Er3+ and Ho3+ ions was sensitised by Cr4+ ions in an yttrium orthosilicate Y2SiO5 (YSO) crystal. The luminescence spectr a of YSO:Cr, Er and YSO:Cr, Ho crystals and the kinetics of the lumine scence of the Cr4+ donor ions were investigated at 77 K and 300 K and analysed. Radiative energy transfer from Cr4+ to Ho3+ was observed in a Y2SiO5:0.2% Cr:0.5% Ho crystal. The Cr4+-Er3+ transfer in a Y2SiO5:0 .1% Cr:1.3%Er crystal at 77 K involved a nonradiative dipole-dipole st atic mechanism in the interval 2.7-24 mu s. The efficiency of nonradia tive energy transfer from Cr4+ to Er3+ was estimated to be 14%-19% at 77 K.