Near-forward Raman study of a phonon-polariton reinforcement regime in the Zn(Se,S) alloy.

We investigate by near-forward Raman scattering a presumed reinforcement of the (A-C,B-C)- mixed phonon-polariton of a A1-xBxC zincblende alloy when entering its longitudinal optical-like (LO-like) regime near the Brillouin zone centre Γ, as predicted within the formalism of the linear dielectric response. A choice system to address such issue is ZnSe0.68S0.32 due to the moderate dispersion of its refractive index in the visible range, a sine qua non condition to bring the phononpolariton insight near Γ. The LO-like reinforcement regime is actually accessed by using the 633.0 nm laser excitation, testified by the strong emergence of the (Zn-Se,Zn-S)-mixed phononpolariton at ultimately small scattering angles. [ABSTRACT FROM AUTHOR]