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BY-NC-ND 3.0 license Open Access Published by De Gruyter June 2, 2014

Eigenfrequencies and Eigenvectors of Polaritons with Application to LiNbO3 I. Long Optical Phonons

G. Börstel and L. Merten

Abstract

The properties of polaritons in uniaxial crystals with an arbitrary number of atoms in the unit cell are discussed in the harmonic approximation. For LiNbO3 , which seems to become a very important substance for applications in tunable Raman lasers, the complete set of eigenfrequencies and eigenvectors (normal coordinates, electric field, electric polarisation) is calculated numerically.

In the limiting case k→∞ (long optical phonons), which is treated in detail in this first paper, an example for each possible type of extraordinary phonon branches is discussed, namely a (T→L) -a (L→T)-, a (T→T)-and a (L→L) -branch of each type. The results are comparable with ex­perimental data only for the frequencies of the 45°-phonons, measured by Barker and Loudon. The agreement is very satisfactory.

Received: 1971-1-30
Published Online: 2014-6-2
Published in Print: 1971-4-1

© 1946 – 2014: Verlag der Zeitschrift für Naturforschung

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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