The self-assembling properties of liquid crystal (LC) are ideal for realizingswitchable optical components. The director organization is strongly determinedby the alignment at the substrate interfaces and photoalignment is aversatile method based on linearly polarized UV light. In this work, a twostepphotoalignment procedure is proposed to pattern the alignment at thesurface. Illumination with uniform polarization or with an interference patternis combined to obtain stripe patterns or square patterns of photoalignment.It can indeed be confirmed that the nematic director follows the varyingazimuthal orientation. By increasing the angle between the two interferingbeams, photoalignment with sub-micrometer resolution is obtained, compatiblewith the dimensions of blue phase (BP) LC unit cell. Homogeneousdomains of BP II with (100) or (110) crystal orientation are obtained and theirKossel patterns are recorded. The two-step photoalignment technique allowsto create patterns with high resolution and to control the orientation of BPLC, which is promising for photonic applications that require single domains.
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