title: From Cartesian to polar: a new POLICRYPS geometry for realizing circular optical diffraction gratings.
abstract: We report on the realization of a liquid crystal (LC)-based optical diffraction grating showing a polar symmetry of the director alignment. This has been obtained as a natural evolution of the POLICRYPS technique, which enables the realization of highly efficient, switchable, planar diffraction gratings. Performances exhibited in the Cartesian geometry are extended to the polar one by exploiting the spherical aberration produced by simple optical elements. This enables producing the required highly stable polar pattern that allows fabricating a circular optical diffraction grating. Results are promising for their possible application in fields in which a rotational structure of the optical beam is needed.
authors.forename: Domenico
authors.initials: D
authors.lastname: Alj
authors.forename: Roberto
authors.initials: R
authors.lastname: Caputo
authors.forename: Cesare
authors.initials: C
authors.lastname: Umeton