Polarisation anisotropy in colloidal photonic crystals

In-depth investigation of the polarisation anisotropy of the reflected and transmitted light in 3-dimensional photonic crystals has been undertaken using the numerical experiment with perfectly ordered colloidal crystal in comparison to measurements of two types of such crystals with intrinsic disorder. Merging of the critical angle of diffraction to the Brewster angle of a crystal as an effective medium has been shown. Equalising of anisotropy magnitudes of different resonances across the range of avoided crossing of their dispersion branches has been observed. The different appearance of the polarisation anisotropy in resonances in transmission and reflectance has been demonstrated. The usually opposite character of the resonance anisotropy with respect to the off-resonance anisotropy has been presented.