Theoretical Analysis of Four-level GSA/ESA Upconverted Luminescence Containing a Nonradiative Process

Unlike conventional three-level GSA/ESA upconversion system,a four-level GSA/ESA upconversion system containing a nonradiative process is presented.The dynamic process and luminescent properties of the upconversion are analyzed theoretically by rate equation model.The results show that the rise process of the upconversion is dominated by the nonradiative relaxation rate of the middle nonradiative level,while the decay process is mainly governed by the relaxation rate of the final excited state level.