Optical excitation of the ~5I_6 level in an Yb:Ho:YLF crystal

摘要

The optical excitation of the ~5I_6 level in Yb:Ho:YLF is studied. Pumping with a wavelength of 953 nm populates the ~2F_(5/2) upper level of Yb~(3+) from where the energy is efficiently transferred to the ~5I_6 upper laser level of Ho~(3+). Pumping is performed with a Ti: sapphire laser. Based on the measured rise times and decay times of the fluorescence from the Yb~(3+) ~2F_(5/2) level, the Ho~(3+) ~5S_2 and ~5I_6 levels the cross relaxation coefficients w_(CR1) (Yb~(3+) ~2F_(5/2) + Ho~(3+) ~5I_8 → Yb~(3+) ~2F_(7/2) + Ho~(3+) ~5I_6), w_(CR2) (Ho~(3+) ~5I_6 + Ho~(3+) ~5I_6→Ho~(3+) ~5S_2 + Ho~(3+) ~5I_8) and w_(CR3) (Yb~(3+) ~2F_(5/2) + Ho~(3+) ~5I_8 →Yb~(3+) ~2F_(7/2) + Ho~(3+) ~5S_2) as well as the ESA cross-section σ_(26) (Ho~(3+) ~5I_6→H~(3+) ~5S_2) are estimated with the aid of a numerical analysis.