External control of a stop band position in a visible spectra of photonic crystal opal infiltrated with nematic LC

Recently photonic crystals with a three-dimensional ordered structure with periodicity of the optical wavelength have attracted attention from both fundamental and practical points of view. The physics and applications of photonic crystals have been active topic of research now. The application of photonic crystals is to create tunable band gap materials especially in visible spectra region, where the gap could be controlled by an external parameter. We have studied transmission and linear dichroism spectra of synthetic opal, refractive index n = 1,342, infiltrated with nematic liquid crystal with averaged refractive index n = 1,596 or with water n = 1,30 and alcohol n = 1,28. We demonstrating that the position of the stop band in the visible spectra is shifted by changing of refractive index of the infiltrated material or by changing the filling factor or by variation of an incidence angle of light.