DIFFRACTIVE OPTICAL-ELEMENTS WITH SPIRAL PHASE DISLOCATIONS

Some geometric transformations cannot be implemented exactly with continuous holographic optical elements (HOEs), since the grating vector field defining the element is not irrotational. In this paper, a new method is presented to implement such transformations. An element is produced by replacing the rotational part of the grating vector by a set of spiral phase dislocations. The method can cope with general transformations, and it is used to produce a HOE to implement a non-rotationally symmetric intensity transformation. The phase dislocations show up as holes in the intensity of the image of the HOE. The results are discussed.