2.5 W continuous wave output at 665 nm from a multipass and quantum-well-pumped AlGaInP vertical-external-cavity...

An output power of 2.5 W at a wavelength of 665 nm was obtained from a quantum-well (QW) and multipass-pumped AlGaInP-based vertical-external-cavity surface-emitting laser operated at a heat sink temperature of 10°C. Intracavity frequency doubling resulted in an output power of 820 mW at a wavelength of 333 nm. To the best of our knowledge, these are the highest continuous wave output powers from this type of laser both at the fundamental wavelength and in frequency-doubled operation. In fundamental wavelength operation, further power scaling by increasing the pump-spot size increased the output power to 3.3 W. However, at this power level, the laser was highly unstable. When the laser was operated at 50% pump duty cycle, a reproducible and stable peak output power of 3.6 W was obtained. These results demonstrate the potential of optical QW pumping combined with multipass pumping for the operation of AlGaInP-based semiconductor disk lasers.