Compact OP-VECSEL-pumped Er:Yb:YAB microchip laser with M² < 1.5 at 1.55 µm

An Er:Yb:YAB crystal laser emitting at 1.55 µm, optically pumped by a vertical external cavity surface emitting 980-nm laser (OP-VECSEL), is reported in this study. To the best of our knowledge, this is the first demonstration of an Er:Yb:YAB laser pumped by an OP-VECSEL. The OP-VECSEL was utilized to pump the Er:Yb:YAB microchip through plano-convex lens. By adjusting the cooling temperature, the output wavelength of OP-VECSEL was tuned to the crystal's absorption peak. The maximum output power of 0.232 W at 1.55 µm with a pump power of 2.32 W at 980 nm was achieved, with a cavity length less than 100 mm. The beam quality factors of the laser output are M²_x = 1.42 and M²_y = 1.38, respectively, better than those of single-end and/or dual-end pumped Er:Yb:YAB microchip lasers.