Abstract: Liquid crystal is a typical soft matter, with excellent external field tunability and hierarchical self-assembly. Here we present our recent work on the use of photo-alignment to manipulate the microstructure and even hierarchical structure of liquid crystals, resulting in various novel physical effects. Liquid crystal microstructures of arbitrary design have been fabri- cated by photo-patterning, which enables flexible and efficient control of the multi-dimensional parameters of light such as the amplitude, phase, polarization and wavelength. Liquid crystal based tunable terahertz devices have also been devised.