IFTA (Iterative Fourier Transform Algorithm) is a polular algrithm used to design an optical element to transform a given light distribution into another desired light distribution. The optical elements can be continuous or multilevel diffractive optical elements (DOE).

IFTA was introduced to characterize a family of algorithms that bounce back and forth between two spaces related by Fourier transform.

ifta_diagram
                        IFTA Diagram

 

IFTA, was first proposed for digital holography by Gerchberg and Saxton for digital holography in the early seventies. It was mostly referred to as an error-reduction algorithm, or Gerchberg-Saxton algorithm.

The error-reduction was tested not to suit for elements with discrete phase values, such as binary or multilevel DOE, due to its tendency to converge to the nearest local optimum, failing to find the desired global optimum.

For the design of phase-only computer-generated holograms (CGH) such as the kinoform, various variations of the IFTA were proposed in the last 20 years.

DOEMaster is based on latest IFTA (Iterative Fourier Transform Algorithm) optimization method. It achieves fast convergence and better uniformity for beam-shaping. DOEMaster can design wide-angle DOE with total diffraction angle up to 120 degree.