Abstract: The influence of phonon distribution on the frequency upconverted fluorescence emission is studied with laser spectroscopy in different matrices and at different ambient temperatures. The spectrum of phonon energy can be adjusted by varying the content of SiO2 in the oxyfluoride glass and glass ceramics, which affects the upconverted fluorescence emission of doped ions. Since the phonon energy depends on the sample temperature, the variation of the temperature can also influence the population rate of 3H4 level in Tm3+ doped low-phonon-energy LaF3 crystal, resulting in a change of the fluorescence upconversion.

Keywords: 
• fluorescence emission /
• phonon /
• nonradiative relaxation /
• fluorescence lifetime