Spontaneous Raman Scattering by Polaritons. II. The Case of CdS and LiNbO₃ Crystals

Abstract

On the base of a general theory of Raman scattering (RS) by polaritons, previously developed by the authors, polariton RS in CdS and LiNbO3 crystals was calculated at scattering radiation with λ1 = 5145 Å and λ1 = 4880 Å, respectively. The angular dependences of RS line integral intensities and besides this for CdS the scattering line shapes were calculated. It is shown in particular that in the CdS scattering spectrum at small angles the auxiliary low‐frequency “photon‐like” line consisting of two similar components should appear besides the usual “phonon‐like” line. In LiNbO3 some scattering variants are studied at the excitation of nine phonon branches of E‐type and of four branches of AI‐type.

Directional Dispersion and Assignment of Optical Phonons in LiNbO3

“…On the basis of the experimental results cited above directional dispersion brandies, Eigen-vectors and Raman scattering cross sections have been calculated by OBUKHOVSKII et al 13 and BORSTEL and MER-TEN 14 . However, experimental results by CLAUS and SCHRÖTTER 15 concerning the directional dispersion Reprint requests to R. CLAUS, Sektion Physik der Universität München, Lehrstuhl J. BRANDMÜLLER, D-8000 Mün-chen 13, Amalienstraße 54/IV.…”

Raman scattering by polaritons under nonstationary conditions. I: The basic principles of the general theory

“…The vectors k,, w are entirely defined too, provided that we know d,, w,. The Equations (2) are chosen in such a way, that they coincide with the conditions for the line centre of stationary scattering [13]. Thus in the stationary problem the dependence of t,,, upon the time would correspond to consideration of the scattering line shape only.…”

Raman scattering by polaritons in Ti:LiNbO3 waveguides

“…(a) 'y-cut': optical axis to be parallel to y-axis as well as perpendicular to pi: (i) extraordinary TEo pump mode eL = (0,1,0); (ii) TMo Stokes mode; (iii) ordinary polariton field polarization ep = (1,0,0);(b) 'z-cut': optical axis to be perpendicular to the film interface: (i) TM, pump mode; (ii) ordinary TEo Stokes mode es = (0, cos 0, sin 0); (iii) ordinary polariton field polarization.The propagation constants PL and p' have been calculated for typical refractive indices of Ti:LiNbO,. * Using the crystal parameters according to Ref 7. we obtain E : .…”