Structured alignment layers for nematic liquid crystals: electron-beam lithography as a tool for advanced photonic...

Nematic liquid crystals (NLCs) enable integrated photonic systems where precise molecular alignment controls optical anisotropy and light guiding. Conventional alignment methods balance anchoring strength, patterning freedom, and scalability with inherent trade-offs. We present polymethyl methacrylate (PMMA) nanogroove alignment layers fabricated by electron-beam lithography (EBL), allowing mask-free, submicron alignment geometries. Systematic variation of the groove width and separation yields controlled nematic alignment, a stable twisted-nematic electro-optic response, and enhanced anchoring. Multidomain patterns, a vortex retarder generating structured light, and spatially patterned waveguides and splitters highlight EBL as a powerful platform for engineered liquid-crystal photonics.