Nematic liquid crystals (NLC) are used extensively in electro-optic devices, such as display, because the alignment of the NLC established by surface anchoring forces can be modified by an applied electric field, thus allowing for change of the effective refractive index for certain light polarizations. In recent years there has been considerable interest in the use of LCs for electrical tuning of the optical properties of photonic crystal (PC) devices, such as the stop band of a photonic crystal,1-3 the emission wavelength of a PC laser, and the diffraction efficiency of grating based devices. Techniques such as mechanical rubbing are effective in producing uniform alignment of NLC on planar surfaces. However, the rubbing process alone is usually insufficient to create a uniform alignment of NLC confined in a 3D microstructure, because the alignment is also affected by local anchoring forces from the microstructure surface and the geometry of the microstructure. Very often a multi-domain structure with many defects form in LC-filled 3D structures, generating an undesired strong scattering, even if the substrates are pretreated with rubbed polymer layers
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