Upconversion luminescence of Ca1−xHoxF2+x and Sr0.98−xEr0.02HoxF2.02+x powders upon excitation by an infrared laser

Fluorite-type Ca1-xHoxF2+x and Sr0.98-xEr0.02HoxF2.02+x powders were synthesized using the co-precipitation from water solution technique. The upconversion luminescence of Ca1-xHoxF2+x and Sr0.98-xEr0.02HoxF2.02+x powders in the visible spectral region upon excitation of I-5(7) level Ho3+ ions and I-4(13/2) level Er3+ ions were studied for the first time. The possibility of visualizing near IR laser radiation using Ca1-xHoxF2+x and Sr0.98-xEr0.02HoxF2.02+x powders is proposed. Optimal compositions of Ca1-xHoxF2+x and Sr0.98-xEr0.02HoxF2.02+x powders for application as visualizers are discussed.