Physical Properties of KY1-xErxF4 Investigated by Photoluminescence

Abstract

Trivalent erbium ions, Er3+, in KY1-xErxF4 crystal produce up-converted photoluminescence (PL) band around 406 nm when excited by 488 or 532 nm photons. By using time-resolved spectroscopy, it was found that the up-conversion arises from the energy transfer processes between the excited Er3+ ions. Thermal behavior reveals that the 406 nm up-conversion is a phonon-assisted process. There is also a secondary up-conversion by level-crossing where a PL band around 520 nm is produced by the 532 nm excitation. High pressure causes the crystal to undergo a structural phase transition, as monitored by the PL it produces.