Scattering of light by a sub-monolayer of randomly packed dielectric microspheres giving color effects in transmission

摘要

In this paper, we show that a two-dimensional random system can display strong structural colors in transmission. Polystyrene microspheres with a diameter between 0.5 and 1μm have been randomly adsorbed onto a glass substrate. In this size range, light is mainly scattered in the forward direction. Consequently, in-plane multiple scattering can be neglected while spheres are not too close to each others. This allows one to use a single scattering approximation to reproduce transmission spectra of the system. Under appropriate conditions, destructive interferences between incident and scattered light can cause a full extinction in the transmission. In our case, transmission can be as low as 5% at some frequency ranges, generating strong color effects. Additionally, the film color changes with the angle of observation. This angular dependant color is reproduced theoretically taking into account multiple scattering between spheres.