Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Semiconductor laser

HL 35.3: Vortrag

Dienstag, 17. März 2015, 11:45–12:00, EW 203

Mode-locked QD-VECSEL emitting picosecond pulses at 650 nm — •Roman Bek, Grizelda Kersteen, Stefan Baumgärtner, Fabian Sauter, Hermann Kahle, Thomas Schwarzbäck, Michael Jetter, and Peter Michler — Institut für Halbleiteroptik und Funktionelle Grenzflächen and Research Center SCoPE, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany

We present a SESAM mode-locked VECSEL emitting at 650 nm with a FWHM pulse duration in the order of a picosecond. A v-shaped cavity with the semiconductor samples as end mirrors and a highly reflective output coupler as folding mirror was used to tightly focus onto the absorber region. As active material, both the gain chip and the absorber contain InP-QDs embedded in Al_0.1GaInP and Al_0.55GaInP. The semiconductor structures were grown by MOVPE in an anti-resonant design. In order to increase the field enhancement and therefore reduce the saturation fluence, SESAM samples were additionally coated with fused silica layers of different thicknesses. For an overall resonant design, the mode locking operation is found to be more stable, but with an increased pulse duration. Therefore we were able to use an output coupler with a slightly reduced reflectivity (99.7 %), resulting in an average output power of more than 10 mW. Current research is made towards intra-cavity frequency doubling of the mode-locked VECSEL.