DESIGN OF DIFFRACTIVE OPTICAL-ELEMENTS WITH OPTIMIZATION OF THE SIGNAL-TO-NOISE RATIO AND WITHOUT A DUMMY AREA

We describe a new approach to suppress undesired diffraction orders in the signal area of a Fourier plane diffractive optical element (DOE). We implement this new approach for the DOE design by a two-stage iter ative Fourier transform algorithm that incorporates an adaptive optimi zation of the signal-to-noise ratio and does not require the introduct ion of a dummy output area outside the field of view. A comparison amo ng this approach and three other approaches are presented on the basis of numerical results from several sample diffraction patterns. (C) 19 97 Optical Society of America.