title: [Study on the excitation mechanism of upconversion red emission from Er3+ under square wave excitation].
abstract: The rise and decay curves of Er3+ 4F9/2 upconversion emission in oxyfluoride tellurite glass were measured under the excitation at 808 nm from a laser diode driven by square waves. The lifetime of the intermediate state could be determined via rise times. Then the accumulation process of the 4F9/2 population was confirmed. The excitation mechanism of up-conversion red emission under 808 nm excitation was confirmed by the rate equations and analyzing the relationship between the time constants of the rise and decay processes and the intermediate state. Square wave excited upconversion emission may also be used for measuring lifetimes of infrared energy levels with a conventional photomultiplier tube.
authors.affiliation: Key Laboratory of Luminescence and Optical Information (Ministry of Education), Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China. donglqlaser@yahoo.com.cn
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Dong
authors.forename: Shi-Hua
authors.initials: SH
authors.lastname: Huang
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Wen
authors.forename: Ying
authors.initials: Y
authors.lastname: Feng
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Duan