A5029026895- Photonic and Optical Devices
- Photonic Crystals and Applications
- Metamaterials and Metasurfaces Applications
- Advanced Antenna and Metasurface Technologies
- Plasmonic and Surface Plasmon Research
- Terahertz technology and applications
- Liquid Crystal Research Advancements
- Microwave Engineering and Waveguides
- Antenna Design and Analysis
- Optical Coatings and Gratings
- Electromagnetic Simulation and Numerical Methods
- Optical Network Technologies
- Advanced Fiber Optic Sensors
- Photonic Crystal and Fiber Optics
- Electromagnetic Scattering and Analysis
- Advanced Fiber Laser Technologies
- Orbital Angular Momentum in Optics
- Superconducting and THz Device Technology
- SARS-CoV-2 and COVID-19 Research
- COVID-19 Clinical Research Studies
- Millimeter-Wave Propagation and Modeling
- Semiconductor Lasers and Optical Devices
- Gyrotron and Vacuum Electronics Research
- Electrowetting and Microfluidic Technologies
- Plant Reproductive Biology
Institute for Microelectronics and Microsystems
2016-2025
Aristotle University of Thessaloniki
2006-2025
National Research Council
2016-2024
Sapienza University of Rome
2018-2023
San Diego State University
2023
Glenn Research Center
2023
University of Illinois Chicago
2023
Ministry of Health
2023
Virginia Commonwealth University
2023
Washington State University Vancouver
2023
Technology to efficiently handle light in the terahertz range is sought for a wide of applications, including nondestructive testing, medical diagnostics, and weapons detection. Liquid-crystal devices are cheap promising, but currently suffer from high operating voltage long response times. The authors exploit coupling between periodically arranged patch resonators external fields propose low-voltage absorber whose reflectance can be modulated nearly 0 90%, with switching times around 50...
In this paper we review the state of art in field liquid-crystal tunable guided-wave photonic devices, a unique type fill-once, molecular-level actuated, optofluidic systems. These have recently attracted significant research interest as potential candidates for low-cost, highly functional elements. We cover full range structures, which span from micromachined on silicon devices to periodic structures and infiltrated crystal fibers, with focus key-applications photonics. Various approaches...
An adaptive-focus lens is a device that capable of tuning its focal length by means an external stimulus. Numerous techniques for the demonstration such devices have been reported thus far. Moving beyond traditional solutions, several new approaches proposed in recent years based on use liquid crystals, which can great impact emerging applications. This work focuses advances crystal lenses with diameters larger than 1 mm. Recent demonstrations and their performance characteristics are...
Abstract Ever since the advent of microwave technology, tunable devices, such as phase shifters, resonators, and antennas, have been indispensable in applications requiring radiofrequency signal filtering, beam shaping, or steering. This necessity becomes even more relevant view a new era high‐bandwidth wireless communications 5G networks, satellite links, advanced radars for sensing safety. As operating frequency is pushed toward millimeter‐wave range beyond, performance traditional...
Large birefringence and its electrical modulation by means of Fréedericksz transition makes nematic liquid crystals (LCs) a promising platform for tunable terahertz (THz) devices. The thickness standard LC cells is in the order wavelength, requiring high driving voltages allowing only very slow at THz frequencies. Here, we first present concept overcoupled metal-isolator-metal (MIM) cavities that allow achieving simultaneously both phase difference between orthogonal electric field...
In this work, a dielectric metasurface consisting of hollow nanocuboids, with ultrahigh quality factor, is theoretically proposed and demonstrated. The variation the hole size cuboid allows for tuning resonant anapole mode in nanoparticles. designed to operate two complementary modes, namely electromagnetically induced transparency narrowband selective reflection. Thanks non-radiative nature resonances, minimal absorption losses materials, near-field coupling among nanoparticles, very high...
In this work, a novel all-dielectric metasurface made of arrayed circular slots etched in silicon layer is proposed and theoretically investigated. The structure designed to support both Mie-type multipolar resonances symmetry-protected bound states the continuum (BIC). Specifically, consists interrupted slots, following paradigm complementary split-ring resonators. This configuration allows silicon-on-glass free-standing metasurfaces arc length split-rings provides an extra tuning...
We provide a critical overview of recent advances in all-dielectric, strongly resonant and gradient metasurfaces, as their performance is pushed to the extreme view emerging flat-optics applications.
We theoretically and experimentally investigate a metasurface supporting silicon-slot quasi-bound state in the continuum (qBIC) mode resonating near-infrared spectrum. The is composed of circular slots etched silicon layer on sapphire substrate. symmetry unit cell reduced order to provide access symmetry-protected mode, whose properties are investigated by finite-element full-wave eigenfrequency analysis. measured transmittance spectra verify excitation qBIC with experimental quality factors...
Using a retrospective cohort study design, we aimed to evaluate the effectiveness of molnupiravir and nirmatrelvir/ritonavir in patients with SARS-CoV-2 who were highly vulnerable.
Abstract The electrically tunable properties of liquid-crystal fishnet metamaterials are theoretically investigated in the terahertz spectrum. A nematic liquid crystal layer is introduced between two metallic structures, forming a voltage-controlled metamaterial cavity. Tuning molecular orientation shown to shift magnetic resonance frequency and its overall electromagnetic response. higher than 150 GHz predicted for common dielectric crystalline materials used technology low applied voltage...
This work proposes the use of refractive index sensitivity non-radiating anapole modes high-refractive-index nanoparticles arranged in planar metasurfaces as a novel sensing principle. The spectral position excited hollow silicon nanocuboids is first investigated function nanocuboid geometry. Then, nanostructured periodic arrays on glass substrate are designed. metasurface parameters properly selected such that resonance with ultrahigh Q-factor, above one million, at target infrared...
An aluminum-based terahertz (THz) wire grid polarizer is theoretically investigated and experimentally demonstrated on a subwavelength thin flexible conformal foil of the cyclo-olefin Zeonor polymer. THz time-domain spectroscopy characterization, performed both flat curved configurations, reveals high extinction ratio between 40 45 dB in 0.3-1 range excess 30 up to 2.5 THz. The insertion losses are lower than 1 almost exclusively due moderate Fabry-Perot reflections, which vanish at targeted...
Metasurfaces with a spatially varying phase profile enable the design of planar and compact devices for manipulating radiation pattern electromagnetic fields. Aiming to achieve tunable beam steering at terahertz frequencies, we numerically investigate metasurfaces consisting one dimensional arrays metal-insulator-metal (MIM) cavities infiltrated liquid crystals (LCs). The spatial is defined by periodic voltage applied on properly selected supercells MIM-cavity array. By means electro-optic...
In this work, a silicon metasurface designed to support electromagnetically induced transparency (EIT) based on quasi-bound states in the continuum (qBIC) is proposed and theoretically demonstrated near-infrared spectrum. The consists of periodic array square slot rings etched layer. interruption by bridge breaks symmetry structure producing qBIC stemming from symmetry-protected states, as rigorously group theory analysis. One found behave resonance-trapped mode perturbed metasurface, which...
Abstract Metamaterials are artificial electromagnetic media structured on the subwavelength scale for controlling propagation of waves by means transformation optics. The research activity is now focusing attaining active metamaterial functionalities, including tunability, and shaping modulation waves. Among all different architectures, soft‐matter‐based metamaterials, or hybrid composites, have gained special importance as they allow a variety tuning strategies to be used, those based...
All-dielectric metasurfaces supporting resonant quasi-bound states in the continuum (qBIC) offer an ideal platform for various applications relying on intense light–matter interaction highly localized and enhanced fields. Here, we propose a dielectric metasurface composed of hollow GaP nanocuboid quadrumers periodically arranged silica substrate. The supports qBIC mode with antiferroelectric field configuration, which is very robust to large perturbations cuboid structure thanks its...
The dispersive characteristics of a photonic crystal fiber enhanced with liquid core are studied using planewave expansion method. Numerical results demonstrate that by appropriate design such fibers can function in single-mode/single-polarization operation, exhibit high- or low- birefringence behavior, switch between an on-state and off-state (no guided modes supported). All the above be controlled application external electric field, specific anchoring conditions structural parameters.
A new class of frequency-selective surface filters (FSS) for terahertz (THz) applications is proposed and investigated both numerically experimentally. periodic FSS array cross-shaped apertures patterned on aluminum, deposited thin foils the low-loss cyclo-olefin polymer Zeonor. Apart from fundamental filtering response elements, we also observe very narrow-linewidth peaks with high transmittance, associated guided-mode resonances in dielectric substrate. The effect filter's geometrical...
In this work, a systematic design of Fabry-Perot cavity antennas based on leaky waves is proposed in the THz range.The use different topologies for synthesis homogenized metasurfaces shows that specific fishnet-like unit-cell particularly suitable efficient radiating devices.Accurate full-wave simulations highlight advantages and disadvantages geometries, thoroughly considering bounds dictated by technological constraints homogenization limit as well.The radiative performance designs...
We experimentally and theoretically demonstrate a class of narrowband transmissive filters in the terahertz spectrum. Their operation is based on excitation guided-mode resonances thin films low-loss cyclo-olefin polymer Zeonor, upon which aluminum stripe patch arrays are patterned via standard photolithography. The engineered to operate low atmospheric loss THz spectral windows, they exhibit very high transmittance quality factors, compact thickness, mechanical stability. dependence their...
A silicon metasurface with a symmetry-protected quasi-dark resonant mode is designed and demonstrated as refractometric sensor tunable notch filter in the near-infrared spectrum. The excited by perturbing periodic array of Si cuboids patterned on glass substrate. Thanks to delocalized nature mode, intense light-matter interaction overlayer material manifested. Such leads strong dependence wavelength refractive index high achievable quality factors, including case lossy materials. High...
We demonstrate the effectiveness of frequency selective surface filters in wireless communications at low terahertz (THz) frequencies. Full-wave simulations pass-band designed 270 GHz and 330 are compared with measurements over 220–360 GHz, showing remarkable agreement. The filter spectral response is used to analytically model a THz filter-based channel for modulated signals. In particular, numerical results an OOK signal good agreement both free-space filtered transmission 14 Gb/s. cases,...