Binary-phase Fourier gratings for nonuniform array generation

This effort describes a design method used to develop a binary-phase Fourier grating that generates an incoherent array of output source points with nonuniform user-defined intensities, symmetric about the zeroth order. Like the Dammann fanout grating approach, the binary-phase Fourier grating uses only two phase levels in its grating surface profile to generate the output array. Unlike the Dammann fanout grating approach, this method provides for the generation of nonuniform, user-defined intensities within the final fanout pattern. The process employs both simulated annealing and nonlinear optimization algorithms to locate solutions to the specified grating design problem. Because the desired grating output is incoherent, each source point of the grating response is assessed in terms of intensity, from which an overall efficiency is calculated. Efficiencies are calculated for each solution and are used to evaluate the relative value of each solution. A final design solution that produces an incoherent, symmetric, user-defined nine spot array is presented.