Effect of temperature on excitation energy transfer and upconversion phenomena in Er:YVO4 single crystals

Abstract Investigation of excitation and decay of Er 3+ in YVO 4 single crystals has been carried out at temperature range from 5 to 500 K. In the limit of low Er 3+ content, the temperature dependence of the 4 S 3/2 decay is not consistent with predictions of multiphonon relaxation model. In heavily doped crystals the 4 S 3/2 decay is governed by cross relaxation process, whose rate grows steadily with increasing temperature. An efficient upconverted luminescence near 550 nm following a cw and short pulse (5 ns) excitation of the 4 I 9/2 level in the system under study has been recorded and analysed. Contribution of the excited state absorption to these phenomena has been considered.