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Dispersion of Exciton Polaritons in a Monoclinic Cyanine Dye Crystal. Evaluation of the Reflectivity on Arbitrary Faces
Author(s) -
Hayne Th.,
Weiser G.
Publication year - 1984
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221230129
Subject(s) - polariton , polarization (electrochemistry) , spectral line , crystal (programming language) , condensed matter physics , exciton , anisotropy , physics , molecular physics , materials science , optics , chemistry , quantum mechanics , computer science , programming language
Normal incidence reflectance spectra of the optically biaxial dye bis(N‐ethyl‐thiazoline‐2yl)‐trimethin cyanine iodide are studied on various crystal faces. The spectra vary considerably because the mixing of different electronic transitions by the electromagnetic wave depends on the orientation of the wavevector k . The polarization of the excited polariton modes rotates in the absorbing region if k is not parallel or perpendicular to a symmetry axis. Strength and position of the optical resonances may deviate strongly from the properties of the underlying excitonic transitions. The spectra agree well with the solutions of the Fresnel equation using a model dielectric tensor which approximates the excitonic transitions as Lorentz oscillators.