Optical diffractive image correlators: a brief history and the newest achievements [Review]

Subject of study. In this study, reported works on the development and application of optical diffractive correlators of two-dimensional spatial signals were reviewed. Aim of study. The aim was to systematically analyze the methods and systems of information processing based on optical diffractive correlators. Method. In this review, methods based on the ability of optical systems to form and filter the spatial spectrum of images were evaluated. Main results. The study presents a review of works in the field of optical diffractive image correlators. Papers devoted to this topic are presented in chronological order and categorized by their applications. The most important results achieved in this field, in the author’s opinion, are discussed. Practical significance. The review will be useful for researchers in the fields of photonics and optical information processing as well as for readers specializing in related areas.