Ultraviolet upconversion luminescence of Gd 3+ and Eu 3+ in nano-structured glass ceramics

Abstract

Ultraviolet multiphoton upconversion emissions of Eu 3+ ( 5 H 3–7, 5 G 2–6, 5 L 6 → 7 F 0) and Gd 3+ ( 6 I J , 6 P J → 8 S 7/2) are studied in the Eu 3+ (or Gd 3+) doped SiO 2–Al 2O 3–NaF–YF 3 precursor glasses and glass ceramics containing β-YF 3 nanocrystals, under continuous-wavelength 976 nm laser pumping. It is experimentally demonstrated that energy transfer from Yb 3+ to Tm 3+, then further to Eu 3+ or Gd 3+ is responsible for the upconversion process. Compared to those in the precursor glasses, the upconversion emission intensities in the glass ceramics are greatly enhanced, owing to the participation of rare earth ions into the low-phonon-energy environment of β-YF 3 nanocrystals. Hopefully, the studied glass ceramics may find potential applications in the field of ultraviolet solid-state lasers.