Holographic technologies: Тraditions and modernity

A selection of scientific articles devoted to the 75th anniversary of the discovery of holography, made by Dennis Gabor in 1947, is presented to the attention of the readers of the Journal of Optical Technology (Opticheski˘ı Zhurnal). Another significant date, 2022, was the 60th anniversary of the day when the results of Yu. N. Denisyuk’s pioneering work in the field of threedimensional holography became available to the general scientific community.
The XIX International Conference on Holography and Applied Optical Technologies (HOLOEXPO Science & Practice 2022), held in September 2022 in St. Petersburg, was dedicated to a wide range of problems of holographic science and technology, as well as adjacent fields of optics and technology, and coincided with the abovementioned anniversaries in Russia.

The main trends in the modern development of holography can be summarized as follows:
1. In the field of augmented reality systems: High interest and market demand for the development of technical solutions for the transmission and formation of images using diffractive waveguides, refractive microoptical elements, and optical elements manufactured using freeform technology. The issues of numerical design and of mass production of optical components, alongside the increase of the significant optical characteristics, are highly relevant.
2. In the field of protective holography: Development of new protective features, including those related to the formation of color holographic images with elements of motion and dynamics; the use of complex synthesized holographic and kinoform structures aimed to reproduce unique visual features, including device-defined ones; as well as the introduction of new photosensitive materials (photopolymers, metamaterials, etc.) into the practice of protective holography.
3. In the field of nanophotonics and structured light: The use of ultrashort pulse lasers alongside the appliance of direct recording and beam structuring allows modified materials to be obtained with various optical properties applicable in a wide range of scientific and technical tasks. The formation of metasurfaces and metamaterials under the influence of laser radiation is among the most widespread areas of applied science.
4. In the fields of creating diffractive and hologram optical elements, holographic interferometry and microscopy, image recognition correlation systems, and holographic memory: Widespread introduction of computer methods for modeling and synthesis of holograms, holographic filters and other components, as well as the use of optical methods for studying subcellular structures and new biophotonic technologies.
The Editorial Board and the Editorial Office of Opticheski˘ı Zhurnal have selected more than 20 of the most significant and original scientific articles devoted to these problems. The first seven articles from this collection are published in this special issue of the journal.
Three articles in this issue are devoted to the classical topic of holographic technologies. Special attention is to be drawn to the fundamental review by N. V. Nikonorov and co-authors, dedicated to photo-thermo-refractive glasses. No less interesting are  the works on chalcogenide glasses and photopolymers.
In recent years, interest has again increased in another classical field of holography application—the technique of numerical design and of manufacturing holographic optical elements as elements of imaging optical systems, gratings for spectroscopy purposes, and narrow-band filters. Three articles are also devoted to this topic. One more article is about the use of dichroic filters.
In subsequent issues of the Journal of Optical Technology, articles devoted to the abovementioned topics will be published, as well as a number of papers on other applications of holography, in particular, the recording of holograms, the creation and application of metasurfaces, elements for controlling structured
light, etc.

Doctor of Physical and Mathematical Sciences, Professor
Vladimir Yurievich Venediktov V. Yu. Venediktov graduated from the Department of Physics of Leningrad State University named after A. A. Zhdanov in 1982. From 1982 to 2015, he worked at the S. I. Vavilov State Optical Institute, where he worked his way up from a research assistant to the head of the Adaptive Optics Laboratory. In 2003, he received the degree of Candidate of Physical and Mathematical Sciences in the specialty “Optics”; in 2006, the academic title “associate professor” in the same specialty; and, in 2012, the degree of Doctor of Physical and Mathematical Sciences, also in the specialty “Optics.” Since 2006, he has been working
at SPbSETU “LETI,” currently as a professor of the Department of Laser Measuring and Navigation Systems. He is also a professor in the Physics Department of St. Petersburg State University.
He is a leading Russian specialist in the field of holography, adaptive and singular optics, optical resonators, as well as optical interferometry and gyroscopy. He has published more than 200 scientific and educational works, including more than 70 articles in leading peer-reviewed journals. He is the author of 4 collective monographs and 12 USSR copyright certificates and Russian Federation patents.