Red, green, and blue upconversion luminescence in ytterbium-sensitized praseodymium-doped lead–cadmium–germanate glass

Abstract

Abstract Blue, green, red, and near-infrared upconversion luminescence in the wavelength region of 480–740 nm in Pr3+/Yb3+-codoped lead–cadmium–germanate glass under 980 nm diode laser excitation, is presented. Upconversion emission peaks around 485, 530, 610, 645, and 725 nm which were ascribed to the 3P0–3HJ (J=4, 5, and 6), and 3P0–3FJ (J=2, 3, and 4), transitions, respectively, were observed. The population of the praseodymium upper 3P0 emitting level was accomplished through a combination of ground-state absorption of Yb3+ ions at the 2F7/2, energy-transfer Yb3+(2F5/2)–Pr3+(3H4), and excited-state absorption of Pr3+ ions provoking the 1G4–3P0 transition. The dependence of the upconversion luminescence upon the Yb3+-concentration and diode laser power, is also examined, in order to subsidize the proposed upconversion excitation mechanism.