Optical spectra of Eu²⁺ ion doped KMgF₃ single crystals grown by Bridgman method

Abstract

High-quality KMgF₃ single crystal containing 0.5 mol% europium (Eu) was prepared by an improved Bridgman method. X-ray diffraction (XRD), photoluminescence spectra and fluorescence lifetime were measured. The results indicate the reduction of Eu³⁺ to Eu²⁺ in the KMgF₃ single crystal. Under the excitation of 259 nm, 370 nm and 394 nm, the sample has two distinct emissions of Eu²⁺:4f⁷→4f⁷(~363 nm) and 4f⁶5d¹→4f⁷ (~440 nm). The substitution site for Eu ion is confirmed. The optical property investigation result shows that the Eu²⁺ doped KMgF₃ single crystal may be used as potential laser media and related materials for optical devices.