Effect of bonding and pumping scheme for Er:SGGG on the 2.8 µm continuous wave laser

We demonstrate the comparative 2.8 μm laser performance of the single and dual end-pumping Er:SGGG composite crystals. The thermal stress distribution reveals the reasons for the performance limitations of the single end-pumping Er:SGGG laser. The output power of 520 mW with a slope efficiency of 10.4% is achieved on the single end-bonding SGGG/Er:SGGG crystal, while excellent beam quality with <i>M_x</i>²/ <i>M_y</i>² of 1.06 and 1.11 is exhibited on the dual end-bonding SGGG/Er:SGGG/SGGG crystal. Through comparison, it is found that the bonding end-cap can optimize the beam quality, while the dual end-pumping scheme can further alleviate the thermal impact of the pump light on the basis of the bonding end-cap, reducing the cracking probability of the crystal during laser operation. This work provides a valuable reference for further exploration of the effects of bonding and dual end-pumping on the Er:SGGG laser performance.