Enhanced performances of diode-pumped sapphire/Er³⁺:Yb³⁺:LuAl₃(BO₃)₄/sapphire micro-laser at 1.5-1.6 μm

A sandwich-type sapphire/Er3+:Yb3+:LuAl3(BO3)4/sapphire micro-laser was fabricated by tightly pressing two sapphire crystals and a Er3+:Yb3+:LuAl3(BO3)4 microchip together, and directly depositing cavity mirrors onto the outside surfaces of the sapphire crystals. Pumped by a continuous-wave 976 nm diode laser, a 1543 nm laser with maximum output power of 1.17 W and slope efficiency of 33% with respect to incident pump power was realized in the sandwich-type micro-laser, whereas a laser with maximum output power of 0.46 W and slope efficiency of 17% was obtained in a monolithic Er3+:Yb3+:LuAl3(BO3)4 micro-laser. Furthermore, efficient 1521 nm continuous-wave and passively Q-switched pulse lasers were also demonstrated in the sandwich-type micro-laser.