Theoretical and experimental investigation of actively Q-switched Tm,Ho:YLF lasers

The quasi-three-level rate equation of continuous wave end-pumped actively Q-switched Tm,Ho:YLF laser is given under considering energy transfer up-conversion and ground state re-absorption. The analytical formula of the pulse energy is derived. The theoretical results show that the overall laser performance is affected by up-conversion effect, and the energy transfer up-conversion effect reduces the pulse energy and the upper level effective lifetime. The practical example of the diode end-pumped actively Q-switched Tm,Ho:YLF is used to verify the present model.