Spectroscopic characterization by up conversion of Ho3+/Yb3+ codoped CdF2 single crystal

Single crystal of CdF2 codoped with the couple Ho3+/Yb3+ with good optical quality were grown by a Bridgman technique after purification of the starting materials. Emission spectra are recorded at room temperature under UV and NIR excitation. The kinetics of the green and red emissions arising from both (5F4, 5S2) and 5F5 excited states of Ho3+ ions are analyzed in the frame of Ho3+→Ho3+ and Yb3+↔Ho3+ energy transfers. The luminescence decays are parametrized using Inokuti-Hirayama model considering dipole-dipole interaction, in the case of UV excitation and also NIR excitation for the green emission, leading to a R0 critical transfer distance of 9–11 Å. The kinetics of the 5F5→5I8 red upconverted emission is analyzed and discussed using a rate equation model. [Display omitted] •Single crystal of CdF2:Ho3+/Yb3+ with good optical quality were grown by a Bridgman technique.•Bright green emission is recorded under both UV and NIR excitations.•The luminescence decays of Ho3+ are parametrized using Inokuti-Hirayama model.•The 5F5. → 5I8 red upconverted emission is discussed using a rate equation model