Narrow linewidth ultraviolet semiconductor disk laser

Here we combine active stabilisation of an AlGaInP-based red semiconductor disk laser (SDL) with intracavity frequency doubling in the same cavity in order to achieve narrow linewidth, <;25 kHz, and tuning at the second harmonic. As compared to other frequency stabilised UV laser systems which require successive external enhancement cavities, each with separate stabilisation, we benefit here from a much simpler setup thanks to the short fundamental wavelength which allows direct intracavity doubling to the UV.