Upconversion dynamics in Er3+-doped YAG
Green, blue, violet and ultraviolet upconversion luminescence is reported at room temperature in a YAG: 10.5% Er3+ crystal pumped by one-colour (647 nm) and two-colour (647 + 618 nm) laser excitation. The upconversion mechanism was studied by means of time-resolved luminescence spectroscopy and the energy flow pathways are described. Based on the results it appears that energy transfer upconversio