Quantitative analysis of different upconversion-mechanism contributions for population of certain level in Er3+-doped YAG

In Er3+:YAG crystal, dependence of the competition between different upconversion (UC) mechanisms for the population of P3∕22 on the exciting wavelength has been observed. An approximate method has been proposed for quantitative analysis of different UC-mechanism contributions by utilizing the excitation spectra of P3∕22 and G9∕22. The sensitive dependence of the dominant UC mechanism and the fluorescence dynamic behaviors on exciting wavelength observed in the experiment could be well reproduced by this simple and effective method.