Dear Colleagues,

In the last few decades, optical sensor technology has attracted considerable attention for employing structured singular beams and devices on their basis in different areas. An important role here is played by advances in technologies of metamaterials, nanophotonics, and fiber optics, as well as the development of methods for measuring mode spectra in complex vortex beams, the latest advances in digital big data processing, and recovering singular beams subject to external perturbations. Therefore, in this Special Issue, we welcome the latest findings from research, ongoing projects, and review articles that can provide readers with information on current research trends and solutions in optical sensor technology development on the basis of structured vortex beams. In addition, a few highly qualified papers selected and extended from the 7th International Conference on Information Technology and Nanotechnology (ITNT 2021) and the International Conference “Digital Singular Optics: Applications and Fundamentals” (DSO'2021) will be included in this Special Issue. The 7th International Conference on Information Technology and Nanotechnology (ITNT 2021) will be held 20–24 September 2021, in Samara, Russia (http://itnt-conf.org/). The International Conference “Digital Singular Optics: Applications and Fundamentals” (DSO'2021) will be held 6–10 September 2021, in Yalta, Crimea (http://singular-optics.org/en/).

The 7th International Conference on Information Technology and Nanotechnology (ITNT 2021) is intended to provide a forum for leading scientists from all over the world to discuss the latest advances in basic and applied research in the field of Information Technology and Nanotechnology, attract young people to advanced scientific research, and share the latest trends in training and research programs for future ITNT specialists. Within the framework of the 7th International Conference on Information Technology and Nanotechnology (ITNT-2021), the Youth School will be held. At the Youth School, young researchers, postgraduate students, and senior students will become acquainted with the scientific achievements in the Conference topics and also with unique laboratories and equipment of the Samara University.

The International Conference “Digital Singular Optics: Applications and Fundamentals” (DSO'2021) is intended to discuss new digital approaches and achievements in the area of singular optics, advances in the development of multifunctional systems and devices, as well as in transmission, storage, and information processing in fiber-optic networks. The approaches of singular optics (including fiber and nonlinear optics and their applications) promote the improvement of optical digital technology. That is why this conference is a unique opportunity to shed light on new standards and digital concepts concerning the physics of phase and vector singularities. The conference plans to present the latest achievements in the field of trapping, transportation, and structuring of microparticles in nanotechnological processes, the use of singular beams in optical cryptography, in optical transmission and information processing systems, as well as conceptual problems associated with key issues in information optics. The International Conference “Digital Singular Optics: Applications and Fundamentals” (DSO'2021) is an international conference for scientists and engineers, researchers and consultants, theoreticians, and practitioners in the fields of advanced optical research, namely, singular optics and related sciences.

The topics of this Special Issue include but are not limited to: design of diffractive optics elements, modeling of diffractive optics elements, manufacturing technology of diffraction optics elements, optical micromanipulation, waveguides, photonic crystals, resonance structures, Bragg gratings, optical calculations, modeling of optical imaging systems, construction of hyperspectral imaging systems, dispersion elements, spectral filters, elements of nanophotonics, technologies for manufacturing nanophotonics elements, modeling of fiber optics, fiber optics manufacturing technology, atmospheric optical communication systems, filtering, enhancement, color mapping, compression, spectral transformations and invariants, segmentation, clusterization, classification, retrieval, feature extraction and selection, descriptors, dimensionality reduction, object detection and tracking, face, gesture and action recognition, 3D vision, shape or relief reconstruction, registration, geometry transformation, geometric and radiometric correction, mosaic, classification, dimensionality reduction, spectral unmixing, change detection, anomaly detection, data fusion, watermarking, authentication, forgery detection, steganography, steganalysis, vectorization, tracing, geospatial analysis and modeling, new methods for data analysis, classification, clustering, regression, dimensionality reduction, density estimation, rank analysis, neural networks, deep learning, big data, applied problems of data mining in medicine, biology, physics, chemistry, economics, humanities, etc.

Prof. Dr. Alexandr Volyar
Guest Editor

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• Optoelectronic and photonic-crystal-fiber sensors 
• Principles of diffraction optics sensors 
• Fiber optic sensing 
• Influence of external perturbations on propagating structured vortex beams 
• Fiber optical vortex sensors 
• Optical vortices in metamaterials 
• Magneto-optical visualization of micromagnetic objects 
• Acousto-optical conversion of vortex beams in various environments 
• Remote vortex sensors 
• Scattering of vortex beams by biological tissues 
• Remote sensors 
• Optical metrology 
• Structured vortex beams in nanophotonic systems and devices 
• Structured vortex beams in turbulent media 
• Vortex beams in birefringent media 
• Data recovery and processing in transmission systems 
• Vortex beams in quantum optics systems 
• Fiber-vortex sensors 
• Imaging optical systems 
• Seeing through scattering media including optical fibers 
• Plasmonic sensors 
• SPR-optical fiber-based biosensors 
• Metamaterial sensors 
• Laser-assistant technology and fabrication 
• Holographic technology for sensors 
• Lab-on-optical-chip 
• Integrated-optic sensors 
• Advanced materials for optical sensing 
• Far-infrared and THz sensors: apparatus and new materials 
• X-ray 2D-4D sensors 
• Single photon detectors 
• Laser complexes for measuring subnanometer vibrations and displacements of micro-and nanoobjects, ultra-small mechanical deformations, and fields of micro- and nanostructures, and the mass of micro- and nanoparticles 
• Sensor networks 
• Sensing and imaging 
• Image sensors 
• Imaging optical systems 
• Adaptive exposure sensors 
• Vision/camera-based sensors 
• Signal processing, data fusion, and deep learning in sensor systems 
• Object detection and tracking 
• Action recognition 
• Machine/deep learning and artificial intelligence in sensing and imaging 
• Internet of Things