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O: Fachverband Oberflächenphysik

O 63: Plasmonics and Nanooptics V

O 63.1: Vortrag

Donnerstag, 14. März 2013, 10:30–10:45, H38

Photothermal control of light propagation — •André Heber and Frank Cichos — Molecular Nanophotonics Group, University of Leipzig, Linnéstraße 5, D - 04103 Leipzig

Photons are an ideal choice when it comes to telecommunication. They can transfer information at high bandwidth over large distances with low losses. Therefore it is desirable to directly manipulate these signals by other photons which is a difficult task as photon photon interactions are intrinsically weak. Different schemes have been proposed to make beams of light interacting with each other. Some of these include nonlinear optical effects, optical resonators and single quantum systems such as single molecules. Our approach relies on the absorption of a single gold nano-particle which is exposed to an optical signal. It dissipates the excitation energy into the environment as heat creating a temperature profile. This particle is embedded into a nematic liquid crystal which changes its state of matter from the birefringent nematic to the isotropic phase at ambient temperature. The polarisation change by the liquid crystal depends on the thickness of the nematic layer. Therefore the transmission of a second laser beam through the nematic layer in polarisation contrast depends on the intensity of the signal beam. We demonstrate a 100 % intensity modulation.