Upconversion luminescence in Thulium-Doped NaYF 4 Nanoparticles Excited by a 980 nm Laser

Upconversion luminescence at ~800 nm based on Thulium-doped NaYF4 nanoparticles excited by a 980 nm laser has been experimentally demonstrated. Under different concentrations, the fluorescence power is proportional to the pump power.