Optically recorded tunable microlenses based on dye-doped liquid crystal cells

We report on optically recorded microlenses in conventional liquid crystal cells doped with the azo-dye methyl-red. The focal length can be tuned electrically and changed in a wide range with just a small variation of the applied dc voltage. No patterned electrodes, built-in polymeric lens, or patterned molecular reorientation are required. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4711203]