Comparison of optical properties between ytterbium-doped Lu2SiO5 (Yb:LSO) and ytterbium-doped Lu2Si2O7 (Yb:LPS) laser crystals

The cross-sections of the transitions 2F7/2 ↔ 2F5/2 of Yb3+ ion in LPS and LSO laser crystals were compared based on the absorption and fluorescence spectra. In Yb:LPS crystal, pump saturation intensity Isat of 8.5 kW/cm2 was obtained, together with minimum pump intensity Imin as low as 0.114 kW/cm2 and gain cross-section σext of 1.7 × 10−21 cm2 at 1068 nm. In the case of Yb:LSO crystal, the Isat of 9.2 kW/cm2 was achieved, as well as minimum pump intensities Imin of 0.138 kW/cm2 and gain cross-section σext of 1.4 × 10−21 cm2 at 1083 nm. It is believed that Yb:LPS can compete with Yb:LSO in quasi-CW and Q-switched operation due to its single crystallographic site characterization and low-cost in growth of Yb:LPS.