The effects of energy transfer upconversion on end-pumped<i>Q</i>-switched Tm, Ho : YLF lasers

Abstract

Based on the model of continuous wave end-pumped quasi-three-level system, the influence of energy transfer upconversion (ETU) on diode-end-pumped actively Q-switched Tm, Ho : YLF lasers is investigated by the rate equation analysis. The analytical expressions of the fractional thermal loading and the pulse energy are obtained. The influences of ETU on the fractional thermal loading and the output pulse energy are analysed. The theoretical results show that the ETU reduces not only the pulse energy but also the effective upper level lifetime of the actively Q-switched Tm, Ho : YLF laser. The practical example of the diode-end-pumped Q-switched Tm, Ho : YLF laser has been used to verify the present model.