BEAM SHAPING IN THE NONPARAXIAL DOMAIN OF DIFFRACTIVE OPTICS

We address the problem of shaping the radiant intensity distribution o f a highly nonparaxial coherent field by means of a diffractive elemen t located in the plane of the beam waist. To be capable of wide-angle energy redistribution the element must necessarily contain wavelength- scale transverse features, and consequently it must be designed on the basis of rigorous diffraction theory. We consider, in particular, wid e-angle Gaussian to flat-top beam shaping in one dimension. Scalar des igns are provided and their validity is evaluated by rigorous diffract ion theory, which is also used for optimization deep inside the nonpar axial domain, where the scalar designs fail. Experimental verification is provided by means of electron-beam Lithography. (C) 1997 Optical S ociety of America.