American Physical Society, Physical review B, 10(88)
DOI: 10.1103/physrevb.88.104303
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We present Raman scattering results on phonon polaritons in single crystals of α-GaN. A detailed theoretical treatment of their dispersion and Raman scattering efficiency in wurtzite-type crystals is given. Pure symmetry polaritons (ordinary and extraordinary) are accessible in near-forward scattering geometry according to the theory. For this purpose, the experimental setup uses rectangular aperture windows in front of the entrance lens. Thus measurements with well defined wave-vector transfer can be realized. The observed dispersion curves and scattering efficiency results are compared with theoretical ones and are found to be in excellent agreement.