Assuming a circularly polarized
input field, any scalar transmission function can be replaced by a unique fringe-orientation function without changing the (monochromatic) optical effect. What’s more, by assuming a linearly polarized input field, one can design
diffractive beam splitters with 100 percent efficiency, a result that is not possible in the realm of scalar optics.
by Hanna Lajunen, Jani Tervo and Jari Turunen