Characterization of Colloidal Crystals by Optical Methods

In this work we present experimental results regarding characterisation of colloidal crystal obtained by vertical deposition technique with polystyrene spheres of 1 mum of nominal diameter. The sample is illuminated with monochromatic coherent light of 632.8 nm wavelength. We use a set of different techniques: direct optical imaging, optical imaging with Fourier space´s filtering, complex demodulation and analysis of the diffracted light. In this manner it is possible to determine the different degree of ordering, infer the number of layers, identify bad spots and grain boundaries and structures of different length scale, in a similar way to that presented recently by Schope, et al. We emphasise that this analysis can be carried out, basically, in the same mounted system and with a low cost in equipment and time