Twentyfold blue upconversion emission enhancement through thermal effects in [formula omitted]-codoped fluoroindate glasses excited at 1.064 μm

Abstract

Infrared-to-visible upconversion emission enhancement through thermal effects in [formula omitted]-sensitized [formula omitted]-doped fluoroindate glasses excited at 1.064 μm is investigated. A twentyfold increase in the 485 nm blue emission intensity as the sample temperature was varied from 20 to 260 °C was observed. The visible upconversion fluorescence enhancement is ascribed to the temperature dependent multiphonon-assisted anti-Stokes excitation of the ytterbium sensitizer and excited-state absorption of the praseodymium acceptor. A model based upon conventional rate equations considering a temperature dependent effective absorption cross section for the [formula omitted] transition of the [formula omitted] and [formula omitted] excited-state absorption of the [formula omitted] agrees very well with the experimental results. © 2000, American Institute of Physics. All rights reserved.