Tm-to-Ho resonant and nonresonant energy transfer in LiYF4

Abstract

Abstract Absorption and luminescence measurements of Tm 3+ and Ho 3+ ions in LiYF 4 :Tm 3+ , LiYF 4 :Ho 3+ and LiYF 4 :Tm 3+ , Ho 3+ crystals were carried out. The data collected were used to determine the Ho 3+ absorption coefficient integral for 5 I 8 → 5 I 7 transition, and the overlap integral between the normalized Tm 3+ luminescence spectrum due to the 3 F 4 → 3 H 6 transition and the Ho 3+ absorption band due to 5 I 8 → 5 I 7 transition. The relevant critical transfer distance ( R o ), that gives a measure of the Tm 3+ –Ho 3+ coupling, was determined considering the Forster type interaction between the ions. It was found to be 22.5 A and 28.8 A at 300 and 78 K, respectively.