Efficient design of direct-binary-search computer-generated holograms

Computer-generated holograms (CGH’s) synthesized by the iterative direct-binary-search (DBS) algorithm yield lower reconstruction error and higher diffraction efficiency than do CGH’s designed by conventional methods, but the DBS algorithm is computationally intensive. A fast algorithm for DBS is developed that recursively computes the error measure to be minimized. For complex amplitude-based error, the required computation for an L-point CGH is reduced by a factor of (L/log2L)1/2. The fast intensity-based algorithm is substantially more complicated, and modifications are considered in order to make the algorithm more efficient. An acceleration technique that attempts to increase the rate of convergence of the DBS algorithm is also investigated.