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O: Fachverband Oberflächenphysik

O 33: Photonics and Nanooptics I: Infrared Spectroscopy

O 33.10: Vortrag

Dienstag, 8. März 2016, 12:45–13:00, H4

Phonon control in a 2D phononic crystals — •Yuning Guo and Thomas Dekorsy — Department of Physics and Center of Applied Photonics, University of Konstanz, 78457 Konstanz, Germany

Due to the ability to confine and mold acoustic waves in periodic nanostructure, the acoustic properties of phononic crystal (PnC) are tailored by designing various kinds of defects, which is suitable for a wide range of applications from transducer technology to filtering and guidance of acoustic waves. The ways of control phonons in 2D PnC are studied in this report. Channel drop filters can access one channel of a wavelength division multiplexed signal while leaving other channels undisturbed, which are essential components of acoustic communication systems. The target dropping frequency is selected and the transmission efficiency is improved by designing different waveguides and a series of cavities in PnC. The self-collimation of acoustic wave can be regarded as a kind of channelless phononic waveguide, which provides another way to control the propagation of phonons. The self-collimation beam can propagate with almost no diffraction along the PnC, which can be used to acoustic imaging, negative refraction etc.. When the self-collimation beam propagates in a PnC with certain defects, those defects behave like mirrors which lead to acoustic wave bending, splitting and phonons trapping. By analyzing the equi-frequency contour, the properties of waves propagating are deduced and the frequency of self-collimation is determined.