Energy transfer and 2.0 μm emission in Tm3+/Ho3+ co-doped α-NaYF4 single crystals

• Cubic NaYF4 single crystals co-doped with ∼1.90 mol% Tm3+ and various Ho3+ concentrations were grown by Bridgman method.
• The maximum fluorescence lifetime was 23.23 ms for Tm3+ (1.90 mol%)/Ho3+ (3.89 mol%) co-doped α-NaYF4.
• The obtained energy transfer rate (WET) and energy transfer efficiency (η) of Tm3+:3F4 are 1077 s−1 and 95.0%, respectively.
• The maximum emission cross section reached 1.06 × 10−20 cm2.

Cubic NaYF4 single crystals co-doped with ∼1.90 mol% Tm3+ and various Ho3+ concentrations were grown by Bridgman method. The energy transfer from Tm3+ to Ho3+ and the optimum fluorescence emission around 2.04 μm of Ho3+ ion were investigated based on the measured absorption spectra, emission spectra, emission cross section and decay curves under excitation of 800 nm LD. The emission intensity at 2.04 μm increased with the increase of Ho3+ concentration from 0.96 mol% to 3.89 mol% when the concentration of Tm3+ was held constantly at ∼1.90 mol%. Moreover, the maximum emission cross section reached 1.06 × 10−20 cm2 and the maximum fluorescence lifetime was 23.23 ms for Tm3+(1.90 mol%)/Ho3+(3.89 mol%) co-doped one. According to the measured lifetime of Tm3+ single-doped and Tm3+/Ho3+ co-doped samples, the maximum energy transfer efficiency of Tm3+:3F4 level was 95.0%. Analysis on the fluorescence dynamics indicated that electric dipole–dipole is dominant for the energy transfer from Tm3+ to Ho3+.

Figure optionsDownload as PowerPoint slide