Spectroscopic ellipsometry on photonic crystals made by self-assembled dye-doped P(S/HEMA) nanospheres

摘要

In the present work the use of Spectroscopic Ellipsometry (SE) for a direct and non-destructive optical and structural characterization of opaline photonic crystals is demonstrated. The analysis is performed on self-assembled dye-doped polymer nanospheres deposited on glass substrates. We study two different polymers beads: PMMA (as well-known reference material) and poly[styrene-(co-2-hydroxyethyl metacry-late)] [P(S/HEMA)]. We show that SE allows to obtain in-rnformation about all the most important optical and geometrical features of the photonic structure as the effective refractive index (n_(eff)), the refractive index modulation, the optical anisotropy, the air/sphere filling fraction, the layer distance and the size of nanospheres. Results are in very good agreement with those obtained by Scanning Electron Microscope (SEM) analysis and Bragg reflection spectroscopy.