Structural changes caused by the optically induced helical inversion in the cholesteric liquid crystal cells with homeotropic anchoring are studied. In a one-step exposure, a sequence of structural transformations "lying left-handed helix - unwound homeotropic state - lying right-handed helix" is realized. In this process, smooth expansion of a left-handed helix, transition to an unwound state, emergence and smooth compression of a right-handed helix was observed. The unwound state was maintained over a rather wide range of exposures. Well-oriented and highly periodic fingerprint textures capable of the above mentioned structural changes were obtained by rubbing the aligning substrates. This allowed for obtaining photo-tunable diffraction gratings and using them to demonstrate new beam steering principle. Also, pitch reversal suggested new options for optical recording, in particular contrast reversal and edge enhancement.
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