Resonant Raman scattering and surface phonon modes of hollow ZnS microspheres

The optical properties of hollow ZnS microspheres were studied. The Raman scattering spectra of the hollow ZnS microspheres depend strongly on the excitation power, and at an excitation power of about I-0/10, a strong resonant Raman scattering spectrum with high-order longitudinal optical modes and weak high-order surface optical modes appeared. The weak surface phonons are sensitive to the surrounding medium and are considered to come from the surface defects of the microspheres. The frequency of the weak surface phonon is in agreement with the prediction calculated on the basis of the dielectric continuum approach. (C) 2007 American Institute of Physics.