Nonresonant Energy Transfer from Er3+ to Yb3+ in LaF3

Abstract

Energy transfer in LaF3; Er, Yb is studied by observing the lifetimes of Er3+ in excited states and the excitation spectra both at room temperature and at 77 °K. It is found that the energy transfer from Er3+ (4S3/2→4I13/2) to Yb3+ (2F7/2→2F5/2) is associated with the emission of three phonons of about 350 cm−1, and that the energy transfer from Er3+ (2H9/2→4F9/2) to Yb3+ accompanied by the absorption of phonons takes place.