Microscopic ellipsometry image of microspheres on a substrate

We performed experimental measurements and theoretical simulation based on an efficient half-space Green’s function method to investigate the diffraction patterns of light scattering from silicon and ZnO microspheres on a substrate. The microscopic ellipsometry image for s- and p-polarized reflectance and their phase difference (Rs, Rp, and Δ) was taken by a modified Optrel MULTISKOP system with rotating compensator configuration for various angles of incidence and wavelengths ranging from 450nm to 750nm. An 80X objective was used and the pixel size for our image is around 200nm. The images obtained display clear diffraction patterns, which is analyzed by an efficient full-wave simulation based on half-space Green’s function method. The near-field distributions obtained theoretically are then converted to far-field images by filtering out the evanescent waves and propagating waves which cannot reach the objective. The experimental results are then compared with simulated images to gain better understanding of the image patterns. Some prominent peaks are observed and attributed to resonances related to whispering gallery modes.