1180 nm VECSEL with output power beyond 20 W

The highest power result for an optically-pumped single-chip vertical external-cavity surface-emitting laser with emission near 1180 nm is reported. The gain mirror was grown by molecular beam epitaxy and incorporated a strain compensated GaInAs/GaAs/GaAsP active region. An intra-cavity diamond heat spreader was attached to the gain mirror for thermal management. In free-running operation, the laser emitted more than 20 W at a mount temperature of about 12°C. The output spectrum was centred between 1165-1190 nm depending on the mount temperature and pump power. By using an intra-cavity birefringent filter, the full width at half-maximum linewidth could be narrowed to ≤1 nm and at the same time achieved approximately 14 W of output power near 1178 nm. Moreover, the lasing wavelength could be tuned over more than 40 nm.