Tunable Microlens Based on Nanoparticle-induced Hybrid Alignment Liquid Crystal

The nanoparticles-induced vertical alignment (NIVA) of the nematic liquid crystals (LC) was proposed to make a tunable liquid-crystal flat microlens with hybrid-aligned nematic (HAN) mode, which was fabricated using micro drop technology. The minute amount of nanoparticle solution was dropped on the selective area, which was surrounded by homogeneous alignment layer. Due to vertical alignment induced by the nanoparticles, the liquid-crystal concave microlens with concentric non-uniform distribution of the refractive index was then formed in the planar LC cell. The divergence effect of this flat lens was observed and its focal length can be electrically controlled at applied voltages.