55 citations · 257 across the 23 of their papers we have counts for
27 papers
Wavefront Engineering for Physical Layer Security in Near-Field Wireless Communications
Sotiris Droulias, Angeliki Alexiou
With wireless transmission exposing information to potential interception by unintended receivers, physical layer security (PLS) offers a promising approach to securing wireless co…
Radial-Angular Resolution Framework for Near-Field Communications
Viviana Centritto, Sotiris Droulias, Angeliki Alexiou
Near-field beamfocusing confines radiated power into a localized three-dimensional focal spot, making the analytical characterization of radial and angular resolution critical for…
Analytical Framework of Radial Resolution for Near-Field Communications
Viviana Centritto, Sotiris Droulias, Angeliki Alexiou
As extremely large antenna arrays (ELAAs) become central to next-generation wireless systems, the transition into the near-field propagation regime enables the exploitation of sphe…
Unified Evaluation Methodology for AI-Native Integrated Sensing and Communication
Filip Lemic, Andra Blaga, Francesco Devoti +24
Integrated Sensing and Communication (ISAC) couples radio sensing, data transmission, and control actions within a single closed-loop system. When Artificial Intelligence (AI)-driv…
Bending beams behind corners: mechanisms, challenges and capabilities for wireless connectivity
Sotiris Droulias, Angeliki Alexiou
Curved beams, that is, beams that are able to propagate on nonlinear trajectories, are often envisioned as ideal candidates for blockage avoidance in future wireless connectivity.…
Enhancing the physical layer security with bending beams
Sotiris Droulias, Giorgos Stratidakis, Angeliki Alexiou
Wavefront engineering for applications in near-field wireless connectivity is gradually becoming common ground. In this landscape, beams that propagate on bent paths are ideal cand…
Ultrafast All-optical control of Multiple Light Degrees of Freedom through Mode-mixing in a Graphene Nanoribbon Metamaterial
Nikolaos Matthaiakakis, Sotiris Droulias, George Kakarantzas
The evolution of optical technologies necessitates advanced solutions for selective and dynamic manipulation of light's degrees of freedom, including amplitude, phase, polarization…
Bending beams for 6G near-field communications
Sotiris Droulias, Giorgos Stratidakis, Angeliki Alexiou
Future wireless connectivity is envisioned to accommodate functionalities far beyond broadband data transmission over point-to-point direct links, enabling novel scenarios, such as…
Hierarchical Localization for Integrated Sensing and Communication
Giorgos Stratidakis, Sotiris Droulias, Angeliki Alexiou
Localization is expected to play a significant role in future wireless networks as positioning and situational awareness, navigation and tracking, are integral parts of 6G usage sc…
Reconfigurable Intelligent Surfaces as Spatial Filters
Sotiris Droulias, Giorgos Stratidakis, Emil Björnson +1
The design of Reconfigurable Intelligent Surfaces (RISs) is typically based on treating the RIS as an infinitely large surface that steers incident plane waves toward the desired d…
Near-field orthogonality and cosine beams for near-field space division multiple access in 6G communications and beyond
Sotiris Droulias, Giorgos Stratidakis, Angeliki Alexiou
Spatial division multiple access (SDMA), a powerful method routinely applied in multi-user multiple-input multiple-output (MIMO) communications, relies on the angular orthogonality…
Vortex inverted pin beams: Mitigation of scintillations in strong atmospheric turbulence
Sotiris Droulias, Michalis Loulakis, Dimitris G. Papazoglou +3
We recently introduced a new class of optical beams with a Bessel-like transverse profile and increasing beam width during propagation, akin to an "inverted pin". Owing to their sp…
Perceptive, Resilient, and Efficient Networks assisted by Reconfigurable Intelligent Surfaces
Giorgos Stratidakis, Sotiris Droulias, Angeliki Alexiou
Wireless communications are nowadays shifting to higher operation frequencies with the aim to meet the ever-increasing demand for bandwidth. While reconfigurable intelligent surfac…
Inverted pin beams for robust long-range propagation through atmospheric turbulence
Sotiris Droulias, Michalis Loulakis, Dimitris G. Papazoglou +3
We introduce a new class of optical beams, which feature a spatial profile akin to an ``inverted pin''. In particular, we asymptotically find that close to the axis the transverse…
Analytical characterization of RIS-aided terahertz links in the presence of beam misalignment
Evangelos N. Papasotiriou, Sotiris Droulias, Angeliki Alexiou
The terahertz (THz) frequency band has recently attracted considerable attention in wireless communications as potential candidate for providing the necessary high bandwidth for de…
Reconfigurable chirality with achiral excitonic materials in the strong-coupling regime
P. Elli Stamatopoulou, Sotiris Droulias, Guillermo P. Acuna +2
We introduce and theoretically analyze the concept of manipulating optical chirality via strong coupling of the optical modes of chiral nanostructures with excitonic transitions in…
Reconfigurable Intelligent Surface: MIMO or radiating sheet?
Sotiris Droulias, Angeliki Alexiou
A Reconfigurable Intelligent Surface (RIS) redirects and possibly modifies the properties of incident waves, with the aim to restore non-line-of-sight communication links. Composed…
Chirality sensing employing PT-symmetric and other resonant gain-loss optical systems
Ioannis Katsantonis, Sotiris Droulias, Costas M. Soukoulis +3
Molecular chirality detection and enantiomer discrimination are very important issues for many areas of science and technology, prompting intensive investigations via optical metho…
Chiral sensing with achiral anisotropic metasurfaces
Sotiris Droulias, Lykourgos Bougas
Recently, we proposed a metasurface design for chiral sensing that (i) results in enhanced chiroptical signals by more than two orders of magnitude for ultrathin, subwavelength, ch…
Chiral sensing with achiral isotropic metasurfaces
Sotiris Droulias
Metasurfaces, the two-dimensional analogues of metamaterials, are ideal platforms for sensing molecular chirality at the nanoscale, e.g. of inclusions of natural optically active m…
Scattering properties of PT-symmetric chiral metamaterials
Ioannis Katsantonis, Sotiris Droulias, Costas M. Soukoulis +2
The combination of gain and loss in optical systems that respect parity-time (PT)-symmetry has pointed recently to a variety of novel optical phenomena and possibilities. Many of t…
PT-symmetric chiral metamaterials: Asymmetric effects and PT-phase control
Ioannis Katsantonis, Sotiris Droulias, Costas M. Soukoulis +2
We investigate the influence of chirality on the PT-symmetric and PT-broken phase of PT-symmetric chiral systems. Starting from the point that transverse magnetic (TM) and transver…
Absolute chiral sensing in dielectric metasurfaces with signal reversals
Sotiris Droulias, Lykourgos Bougas
Sensing molecular chirality at the nanoscale has been a long-standing challenge due to the inherently weak nature of chiroptical signals, and nanophotonic approaches have proven fr…
Accessible phases via wave impedance engineering with PT-symmetric metamaterials
Sotiris Droulias, Ioannis Katsantonis, Maria Kafesaki +2
Optical systems that respect Parity-Time (PT) symmetry can be realized with proper incorporation of gain/loss materials. However, due to the absence of magnetic response at optical…