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The influence of polariton motion on the polariton Raman scattering spectra
Author(s) -
Strizhevskii V. L.,
Yashkir Yu. N.,
Ponath H.E.
Publication year - 1975
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.2220690243
Subject(s) - polariton , scattering , physics , condensed matter physics , intensity (physics) , raman scattering , spectral line , group velocity , phonon , raman spectroscopy , molecular physics , optics , quantum mechanics
The influence of the relative group velocity finiteness of the scattering polariton on the polariton Raman scattering (RS) intensities is discussed. It is proved that this effect is not very essential only in the region of polariton frequencies ω p near the frequency ω f of the corresponding polar mechanical phonon because here the relative group velocity ξ p of the polariton is small. But the influence of the group velocity ξ p finiteness appears to be essential in the case of sufficiently distant frequencies ω p from ω f . This influence results not only in essential quantitative changes but also in qualitative changes, in particular, of the angular dependence of the polariton RS intensity. It is manifested particularily in the vicinity of the „critical” scattering angles where the neglection of this effect distorts absolutely the character of the above‐mentioned dependence. The ξ p ‐finiteness influence is illustrated by numerical calculations for a number of real crystals (ZnO, ZnSe, GaP, CdS, LiIO 3 ). Experimental investigations are made of the RS‐intensity angular dependence in the region of the upper polariton branch in LiIO 3 crystals in the vicinity of the critical scattering angle. The results confirm the conclusion of the theory about the essential influence of the effect mentioned above on the polariton RS intensity.