Liquid crystal microlens arrays recorded by polarization holography

We report the characterization of diffractive microlens arrays (MAs) using a polarization holographic approach assisted by a spatial light modulator (SLM), in a nematic liquid crystal (NLC) cell. The MAs were recorded in the photoaligning substrates of the cell and then replicated in the NLC bulk, through the surface interactions. The transparency of the NLC on a wide range of wavelengths and the ability to tune its optical birefringence, through an external voltage, allowed us to create MAs with high efficiency. We have presented the results obtained for diverse MAs configurations, composed by spherical and cylindrical microlenses and characterized by different focal lengths. The efficiency reaches a value of 90%, at a wavelength of 633 nm.