Enhanced mid-infrared luminescent properties of Ho,Re:CNGG (Re Pr, Eu, Tb) crystals co-doped with deactivating ions

Crystals of 2 at.% Ho:CNGG co-doped with 0.2 at.% deactivating ions (Pr 3+ , Eu 3+ , Tb 3+ ) were successfully grown using the micro-pulling-down ( μ -PD) technique for the first time. Detailed investigations were conducted on absorption spectra , fluorescence spectra , and lifetime decay curves. The 2 at.% Ho, 0.2 at.% Pr:CNGG crystal exhibits a broad absorption band at 1142 nm, with full width at half maximum (FWHM) values of 88.5 nm. This crystal composition shows the most intense emission at 2860 nm, with FWHM of 181 nm. The luminescent lifetime ratio ( 5 I 6 / 5 I 7 ) and transition efficiencies of Ho,Pr:CNGG at approximately 3.0 μm are also the highest, measuring 0.107 and 70.48 % (0.105 and 69.96 % for Ho,Eu:CNGG, 0.090 and 65.08 % for Ho,Tb:CNGG). These results suggest that Pr 3+ demonstrates superior performance in mitigating self-termination and enhancing population inversion compared to the other deactivating ions. • Ho,Re:CNGG (Re Pr, Eu, Tb) crystals were grown by the micro-pulling down method. • The crystal structure, spectra (including absorption, emission and micro-photoluminescence spectra) were investigated. • The effect of deactivating ions on the emission spectroscopic properties of Ho 3+ 3 μm wavelength region was evaluated.