«Kharkiv Quantum Seminar» invites you to a lecture dedicated to the
World Quantum Day, which will take place on April 14, 2026, at 11:00 in an online format.
Lecturer: Oleksiy Nikitin (Alexey Nikitin), Donostia International Physics Center, Donostia – San Sebastián, Spain.
Lecture topic: «Hyperbolic light» (Hyperbolic light).
Abstract:
The propagation of light through various media has long been a subject of fundamental interest in physics. Optical phenomena such as diffraction, scattering, and emission are not only rich in physical content but also play a central role in applications in information processing, visualization, security, and medicine, making research in optics both scientifically and socially significant. While most optical effects in ordinary isotropic media are well studied, the behavior of light can change drastically in strongly anisotropic materials, leading to astonishing and less explored phenomena. Notably, some van der Waals crystals can support polaritons — electromagnetic waves associated with dipolar excitations in matter. In these materials, the dispersion relation of polaritons (which links energy and momentum) can take on a hyperbolic character. This hyperbolic dispersion leads to polaritons that propagate only along certain directions, demonstrating very counterintuitive effects such as negative reflection and refraction, negative phase and group velocities, channeling (restricted propagation along narrow angular sectors), and focusing on scales smaller than the wavelength.
In his report, Professor Oleksiy Nikitin will provide an overview of the field of hyperbolic nano-optics, explain the fundamental physics of hyperbolic polaritons, and demonstrate the latest experimental achievements. It will be shown how these unusual light-matter interactions can be observed, interpreted, and potentially used for new optical functionalities. The presentation will conclude with a discussion of promising directions for future research.
About the lecturer:
Professor Oleksiy Nikitin studied in the graduate program at the Kharkiv Institute of Radiophysics and Electronics named after O. Ya. Usikov of the NAS of Ukraine from 2001 to 2005. In 2006, he worked as a postdoc at the University of Zaragoza (Spain), and then in 2013 he obtained a position as a research fellow Ikerbasque Fellow at the Nanophysics Research Center, San Sebastián (Spain). In 2018, he joined the Donostia International Physics Center (Spain) as an associate professor, and in 2025 he became a research professor.
The scientist has worked on various topics in nanophotonics and two-dimensional materials, with scientific interests focused on polaritons in anisotropic van der Waals materials and the theory of near-field optical microscopy. He has published over 100 scientific articles, which have received more than 12,000 citations. He contributed to the discovery of plasmonic polaritons in graphene and topological insulators, hyperbolic phonon polaritons in various polar crystals such as h-BN, and developed several methodologies for modeling and interpreting nanoimaging using near-field microscopy.
Event organizers: B. I. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine (Doctor of Physical and Mathematical Sciences Serhiy Shevchenko) and National Scientific Center «Kharkiv Institute of Physics and Technology» (Corresponding Member of the NAS of Ukraine Andriy Sotnikov).
Zoom link:
https://us06web.zoom.us/j/84858248436?pwd=9ZMtSUCFXUuQXmb9ndDgVSEL2vfDyh.1
Conference ID: 84858248436
Conference code: 929397
According to the information from the B. I. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine