Dynamics and spectroscopy of infrared-to-visible upconversion in erbium-doped cesium cadmium bromide (CsCdBr3:Er3+)

Abstract
Trivalent erbium ions in CsCdBr3 exist predominantly as dimers along one-dimensional lattice chains. Very efficient upconversion from near-infrared to various visible wavelengths was observed. 2 H9/2 4 I15/2 (414 nm) and 4 F7/2 4 I15/2 (493 nm) fluorescence dominated for 4 I15/2 4 I9/2 (801 nm) and 4 I15/2 4 I11/2 (984 nm) excitation, respectively. Simultaneous excitation at 801 and 984 nm preferentially populated 4 F5/2, giving 4 F5/2 4 I15/2 (455 nm), 4 F5/2 4 I13/2 (651 nm), and, by cross relaxation, 4 F9/2