RESUMO
We report highly efficient laser operation of praseodymium-doped LiYF(4) in the green spectral range. The influence of the crystal length and pump light focusing on the laser performance has been studied. The pump radiation was delivered by InGaN laser diodes. Optimizing the setup for a 2.9 mm long crystal with a doping concentration of 0.5% led to an electric to green laser power conversion efficiency as high as 7.4%. With 500 and 1000 mW of pump light power, output powers of 179 and 358 mW have been reached, respectively. With respect to absorbed power, slope efficiencies of up to approximately 60% have been achieved.
RESUMO
Quantum dot (QD) semiconductor saturable absorber mirrors (SESAMs) offer a larger design freedom than standard quantum well (QW) SESAMs. QD density, QD growth conditions, number of QD-layers, and post-growth annealing were optimized to independently reduce the saturation fluence and adjust the modulation depth for an antiresonant SESAM that supported for the first time passive modelocking of a vertical external-cavity surface emitting laser (VECSEL) with the same spot size on gain and absorber. The same spot size is a requirement for the modelocked integrated external-cavity surface emitting laser (MIXSEL) concept which enables wafer-scale fabrication of the ultrafast semiconductor laser. The antiresonant SESAM design has low dispersion, is less susceptible to growth errors, and is therefore very promising for short pulse generation and MIXSEL integration.
