Single longitudinal-mode passively Q-switched 1537 nm Er:Yb:Lu₂Si₂O₇ pulse microchip laser

A single longitudinal-mode passively Q-switched 1537 nm pulse microchip laser was realized in an Er:Yb:Lu₂Si₂O₇ crystal. The effects of the pump beam diameter and output mirror transmission on pulse characteristics of the Er:Yb:Lu₂Si₂O₇ microchip laser were investigated, when a Co²⁺:MgAl₂O₄ saturable absorber with an initial transmission of 95% was used. At an absorbed pump power of 3.4 W, a 1537 nm single-longitudinal-mode pulse laser with energy of 25.8 µJ, repetition frequency of 0.89 kHz, duration of 4.3 ns, and peak output power of 6.0 kW was obtained, when the pump beam diameter and output mirror transmission were 420 µm and 3.0%, respectively. The beam quality factor of output laser with TEM₀₀ mode was less than 1.3.