Near-field optical images of ordered polystyrene particle layers and theirphotonic band effect

To study the origin of the SNOM image contrast patterns observed for sample s composed of transparent materials only, we have investigated the transmis sion SNOM images of an ordered polystyrene particles layer for Various wave lengths of incident light. We have found a drastic change in the SNOM image patterns as the incident wavelength is scanned across the resonant wavelen gth of the photonic bands of the layer. Observed wavelength dependence of t he near-field intensity of the layer was found to be in a good qualitative agreement with the theoretical calculation in terms of the photonic band ef fect. (C) 2000 Elsevier Science B.V. All rights reserved.