Fluorescence upconversion in Sm-doped Gd2O3

Abstract
We report the observation of efficient fluorescence upconversion in Sm-doped Gd₂O₃ nanopowders prepared by the spray pyrolysis method. The blue upconversion emission was observed with low-power continuous-wave excitation at 514, 561, 594, and 633 nm and with a pulsed femtosecond at 710 nm, in a laser scanning confocal microscope. This result indicates that Sm-doped Gd₂O₃ has the potential as a fluorescent label that may be excited in red, yellow, and green with blue emission