Berlin 2012 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster: New Instruments and Methods

CPP 15.18: Poster

Tuesday, March 27, 2012, 18:15–20:15, Poster A

Improving the performance of liquid crystal lasers by electric fields — •Jürgen Schmidtke, Lu Lu, and Heinz-Siegfried Kitzerow — Department Chemie, Universität Paderborn, Germany

During the past decade, self-assembled photonic band edge lasers based on dye-doped cholesteric liquid crystals have attracted considerable interest as tunable, miniature light sources. We demonstrate that the lasing threshold and slope efficiency of a liquid crystal laser can be improved by application of an electric field: Using a dye-doped cholesteric liquid crystal with negative dielectric anisotropy as the DFB laser structure, emission characteristics improves with increasing ac electric field along the cholesteric helix. Possible reasons are a partial suppression of thermally driven director fluctuations, as well as a stabilization of the planar cholesteric texture against disturbances by the optical pumping process.