Iterative Fourier-transform algorithm of synthesis of a kinoform with the use of the operation of predistortion of an object

A modified IFT-algorithm of synthesis of a kinoform is presented. In this method, two object-dependent filters (the amplitude (A) filter and the phase (P) one) are formed in the object plane in the process of iteration, rather than one phase filter, as usual. Both these filters participate in the formation of the phase structure of a kinoform. The use of two degrees of freedom (A, P) in the object plane instead of one degree (P) accelerates the convergence of the IFT-algorithm and allows one to reach significantly less values of the amplitude variance in a reconstructed image as compared with those within the available methods. The results of optical and model experiments confirming the efficiency of the method are given. It is found that the method is most efficient for binary objects. The method is generalized to the case of off-axis kinoforms. A simple method to introduce the carrier frequency into the structure of an axial kinoform is proposed. An image reconstructed by an off-axis kinoform is free from the noises with zero and close frequencies caused by the nonideality of both the phase mode of operation of a SLM and the effects of quantization of the registered phase.