ИСТИНА

Liquid crystal (LC) metasurfaces self-assemble on rubbed polyimide layers periodically patterned with a focused ion beam (FIB) locally flipping the surface anchoring from planar to vertical. Imprinting various patterns by digitally controlled FIB establishes micro-scale LC modulations imparting specific optical path profiles to the transmitted light and enabling versatile optical functions. Upon optimizing the alignment patterns analytically and numerically, we produce superperiodic LC metasurfaces performing a 60% efficient anomalous refraction of blue light into +1 diffraction order. Importantly, the diffraction can be switched by low-voltage signals within a few milliseconds. Subjecting both substrates to complementing optimized FIB-patterns, we produce double-sided LC metasurfaces with twice larger range of optical path modulation enabling efficient deflection of light in the wavelength range of 500-700 nm into +1 diffraction order and redirecting up to 40% of blue light into +2 diffraction order. For comparison, imprinting differently optimized stripe patterns establishes the formation of LC analogs of one-dimensional Dammann gratings, distributing the blue light uniformly into 11 diffraction orders (Fig.1d). We discuss other intriguing functionalities which can be performed by LC metasurfaces and the nature of their remarkably fast electro-optics.