Optical beam shaping systems and methods can include an illumination source and a diffractive waveplate diffuser. The diffractive waveplate diffuser includes a layer of patterned optically anisotropic material. In one embodiment, the layer of patterned optically anisotropic material is fabricated in the form of patterned, optically anisotropic liquid crystal polymer. In another embodiment, the layer of patterned optically anisotropic material is a layer of liquid crystal, the diffractive waveplate diffuser also includes two alignment layers and two transparent conductive coatings, and the properties of the liquid crystal layer are controlled by the application of an electric potential between the two transparent conductive coatings. A method is provided for designing the alignment pattern of the layer of optically anisotropic material.