Modification of the Gerchberg-Saxton algorithm for the generation of specle-reduced intensity distributions of micrometer and submicrometer dimensions

The Gerchberg-Saxton (GS) algorithm is a popular method for the design of diffractive optical elements (DOEs) that can generate predefined complex light distributions. Nowadays, this algorithm is widely used in holography, optical tweezers, and laser nanopatterning. However, the conventional version of the GS algorithm and its various modifications proposed to date have some limitations related to the presence of speckle patterns in the structure of the generated intensity distributions. We present a new modification of the GS algorithm, which allows one to design pure-phase transmission functions of DOEs that generate highly efficient ( > 60%) and highly uniform ( > 70%) speckle-reduced intensity distributions of micrometer and submicrometer dimensions. The proposed modification is based on a zero-padding operation that allows one to decrease the sampling interval for a target image defined as the desired intensity distribution. DOEs designed in such a way can be used for laser micromachining and the fabrication of structured nano- and micropatterns for modern applications of nanophotonics.