Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 15: Poster 1: Quanteninformation, Quanteneffekte, Laserentwicklung, Laseranwendungen, Ultrakurze Pulse, Photonik

Q 15.45: Poster

Montag, 14. März 2011, 16:30–19:30, P1

mode interaction in ZnO random lasers — •Janos Sartor, Daniel Schneider, Felix Eilers, Dirk Silber, Claus Klingshirn, and Heinz Kalt — Institut für Angewandte Physik, Karlsruhe Institute of Technology (KIT) 76128 Karlsruhe (Germany)

Random lasing is a phenomenon found in strongly scattering materials that provide sufficient optical gain. Optically pumped ZnO powder with a mean grain size in the order of the wavelength is such a system and provides excellent conditions to examine random lasing activity. In this system optical modes with different degrees of localization can be observed. Our work concentrates on the characterization of single random lasing modes and their interactions. In samples of reduced size the strong fluctuations typical for random lasers can be suppressed and almost stable emission from single modes can be observed. However at higher excitation densities additional modes appear influencing the formerly stable modes. Once multiple modes begin to lase at the same time, fluctuations of spectral mode positions are observed. This behavior can be explained by carrier density fluctuations caused by spatially overlapping modes.