An integral imaging system may include a lens unit. The lens unit may include a first substrate; a second substrate; a first electrode on the first substrate; a second electrode on the second substrate; a liquid crystal layer between the first and second substrates; and an array of nanostructures protruding from the first substrate into the liquid crystal layer. The first and second electrodes may be configured to apply one or more voltages to the array of nanostructures. When the one or more voltages are applied to the array of nanostructures, one or more electric fields may be formed between the array of nanostructures and the second electrode, varying an arrangement of molecules in the liquid crystal layer and forming a refractive index distribution in the liquid crystal layer.