Article
Physics, Multidisciplinary
Wilton J. M. Kort-Kamp, Abul K. Azad, Diego A. R. Dalvit
Summary: Space-time quantum metasurfaces provide a compact platform for manipulating quantum light, allowing continuous tuning of coherent light-matter interactions in space and time. They enable arbitrary control of the spectral, spatial, and spin properties of nonclassical light, leading to tailored entanglement of single photon degrees of freedom and generation of steered and vortex photon pairs. These metasurfaces have the potential to enable novel photonic functionalities, such as encoding quantum information into high-dimensional color qudits and generating reconfigurable hyperentanglement for high-capacity quantum communications.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Yangyang Fu, Yuan Tian, Xiao Li, Shili Yang, Youwen Liu, Yadong Xu, Minghui Lu
Summary: In this study, a new method for achieving robust asymmetric generation of acoustic vortex field through dual-layer metasurfaces is introduced. This is achieved by controlling the intrinsic topologic charges and the parity of geometry design. The underlying physics is contributed to the one-way process of orbital angular momentum transition ensured by the broken spatial symmetry and the external topologic charge from the vortex diffraction. The novel phenomenon is experimentally demonstrated, providing new routes to manipulate the asymmetric response of vortex fields and potential applications in passive OAM-based diodes.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Feng Mei, Geyang Qu, Xinbo Sha, Jing Han, Moxin Yu, Hao Li, Qinmiao Chen, Ziheng Ji, Jincheng Ni, Cheng-Wei Qiu, Qinghai Song, Yuri Kivshar, Shumin Xiao
Summary: The authors demonstrate an efficient way to generate high-purity vortex beams by applying optical neural networks to cascaded phase-only metasurfaces. Specifically, they present record-high-quality Laguerre-Gaussian (LGp,l) optical modes with polynomial orders p = 10 and l = 200 with purity in p, l and relative conversion efficiency of 96%, 85%, and 70%, respectively.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Min Wang, Lieyu Chen, Duk-Yong Choi, Shuangyin Huang, Qiang Wang, Chenghou Tu, Hua Cheng, Jianguo Tian, Yongnan Li, Shuqi Chen, Hui-Tian Wang
Summary: Twisted photons have the potential to carry an unlimited amount of orbital angular momentum (OAM), which is crucial for quantum communication and testing quantum theory. However, current methods for characterizing OAM quantum states have limitations in miniaturization. This study presents a scheme using all-dielectric metasurfaces composed of birefringent meta-atoms to reconstruct the density matrix of single photon OAM quantum states. The researchers also measured the Schmidt number of OAM entanglement by multiplexing multiple degrees of freedom. This work represents a step towards practical applications of quantum metadevices in free-space quantum imaging and communications.
Article
Engineering, Electrical & Electronic
Karim Achouri, Ville Tiukuvaara, Olivier J. F. Martin
Summary: There is a growing need to accurately model the angular scattering response of metasurfaces for optical analog processing applications. The current metasurface modeling techniques are limited to small angular spectrum transformations. This work aims to overcome this limitation by improving the modeling accuracy and providing a better description of the angular response of metasurfaces. The newly derived multipolar model demonstrates a substantially better modeling accuracy than the standard dipolar model.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Multidisciplinary Sciences
Cormac McDonnell, Junhong Deng, Symeon Sideris, Tal Ellenbogen, Guixin Li
Summary: The use of broadband THz emitters based on Pancharatnam-Berry phase nonlinear metasurfaces allows for precise control and tuning of THz waves.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Yinhui Kan, Xujing Liu, Shailesh Kumar, Sergey I. Bozhevolnyi
Summary: This paper develops a holography-based approach to flexibly design QE-coupled metasurfaces on-chip, which generate far-field quantum emission with specific spin and orbital angular momenta. The method enables multichannel quantum emission with multiple degrees of freedoms, providing a powerful platform for quantum nanophotonics.
Article
Environmental Sciences
Sergey Y. Matrosov
Summary: The statistical relationships between Z(DR) and Z(e) can effectively distinguish between warm rain and stratiform rain, with warm rain having smaller Z(DR) values on average but still following a relative trend due to an abundance of smaller drops. Applying the Z(DR)-Z(e) relation can correctly classify different types of precipitation, with warm rain requiring separate identification for more accurate precipitation estimations.
Article
Engineering, Electrical & Electronic
Bakytgul Yerezhep, Constantinos Valagiannopoulos
Summary: The article discusses the conditions and constraints for stability in configurations utilizing gain media, and presents an analytical method for determining unstable poles in photonic setups. The absorbing and scattering response of the structure reveals performance limits and dynamics, assisting in device modeling and design for applications including radiation pattern control, angular momentum transformation, active cloaking, and reconfigurable wavefront manipulation.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Constantinos Valagiannopoulos, Adilkhan Sarsen, Andrea Alu
Summary: Nonlinear materials can exhibit bistability, which can find direct application to photonic memory devices. Impedance metasurfaces producing hysteresis responses with respect to impinging beam angle under a fixed intensity profile can open new avenues towards the design of photonic systems supporting a wide range of fixed-power memory functionalities.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Nanoscience & Nanotechnology
Luca Mascaretti, Andrea Schirato, Paolo Fornasiero, Alexandra Boltasseva, Vladimir M. Shalaev, Alessandro Alabastri, Alberto Naldoni
Summary: Solar-thermal technologies using plasmonic metasurfaces show great potential in photothermal catalysis by efficiently converting solar energy to heat, achieving broadband light absorption, and promoting faster reaction rates. However, their application in this field has been largely overlooked.
Article
Multidisciplinary Sciences
Adelin Patoux, Gonzague Agez, Christian Girard, Vincent Paillard, Peter R. Wiecha, Aurelie Lecestre, Franck Carcenac, Guilhem Larrieu, Arnaud Arbouet
Summary: This work investigates the influence of fabrication errors on the optical response of optical metasurfaces and quantitatively assesses the tolerance to these errors through extensive numerical simulations. A silicon nanoresonator-based metasurface designed, fabricated, and characterized as a beam deflector in the near-infrared range is used to illustrate the results.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Jianfeng Zhu, Mengze Li, Jiexin Lai, Yang Yang
Summary: This work demonstrates a polarization-maintaining metasurface for spin-decoupled beam shaping using multimaterial additive manufacturing. The wavefronts of LHCP and RHCP can be independently controlled while maintaining the same spin state.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Xiang-Yu Zeng, Yu-Qin Zhang, Rui-Rui Zhang, Xiao-Rong Ren, Zi-Jun Zhan, Man-Na Gu, Rui Sun, Chun-Xiang Liu, Chuan-Fu Cheng
Summary: Metasurfaces with orthogonal nano-slit pairs arranged on spirals are proposed to generate vector beams of Bell-like states and slanted polarizations. The design is based on the theoretically derived parameter condition for manipulation of the two vector vortex modes, satisfied by matching the rotation order m, the spiral order n, and incident polarization helicity sigma. Linear polarization states of the vector beams are controlled by the initial orientation angle of slit pairs.
Article
Physics, Multidisciplinary
Zhiqiang Du, Zhengyong Song
Summary: Due to the increasing complexity of modern communication systems, the requirements for electromagnetic wave are becoming more and more rigorous. Metasurfaces based on Ge3Sb2Te6 are designed to control electromagnetic wavefront in the mid-infrared range by changing the state of Ge3Sb2Te6. By designing specific structures, deflection of electromagnetic wavefront and vortex beams with orbital angular momentum can be achieved. This design may lead to novel types of metasurfaces.
Article
Engineering, Aerospace
Felix Cuervo, Arturo Martin-Polegre, Fernando Las-Heras, Danielle Vanhoenacker-Janvier, Joel Flavio, Michael Schnnidt
Summary: This paper introduces a new propagation experiment that aims to extend the characterization of the Earth-space channel to the W band and low Earth orbits (LEOs).
INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING
(2022)
Editorial Material
Environmental Sciences
Alberto Najera, Rebeca Ramis, Fernando Las-Heras Andes, Concepcion Garcia-Pardo, Jose I. Alonso, Jesus Gonzalez-Rubio, Antonio Hernando, Javier Lafuente Martinez, Francisco Vargas Marcos
ENVIRONMENTAL RESEARCH
(2022)
Article
Chemistry, Physical
Maria Elena de Cos Gomez, Humberto Fernandez Alvarez, Alicia Florez Berdasco, Fernando Las-Heras Andres
Summary: Three metasurfaces (MTS) are designed to be combined with a series end-fed 1 x 10 array antenna to achieve imaging applications in the millimeter frequency range. The MTS-array combination reduces secondary lobes, increases FTBR, widens operation bandwidth, enhances gain and radiation efficiency, while maintaining the size. The envisioned application is collision avoidance for visually impaired people at a medium-long distance.
Article
Geochemistry & Geophysics
Maria Garcia-Fernandez, Guillermo Alvarez-Narciandi, Yuri Alvarez Lopez, Fernando Las-Heras
Summary: The usage of unmanned aerial vehicles (UAVs)-based ground penetrating radar (GPR) systems has gained interest due to their advantages over ground-based systems in terms of contactless inspection and capability to reach difficult-to-access areas. Improving the scanning throughput while maintaining imaging capabilities is a challenge for these systems. This contribution presents an array-based GPR-SAR system for subsurface imaging, which significantly improves the scanning throughput and provides enhanced detection capabilities through the coherent combination of all transmitting-receiving channels of the array.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Engineering, Electrical & Electronic
Yuri Alvarez Lopez, Jaime Laviada, Ana Arboleya, Fernando Las-Heras
Summary: Synthetic aperture radar (SAR)-based microwave imaging systems are widely used in various applications. The scanning speed is a crucial factor in SAR imaging systems, and widening the distance between measurements can increase it. However, this causes the presence of grating lobes that degrade the quality of microwave SAR images. To address this issue, a novel methodology is proposed in this study, which incorporates the amplitude and phase of the field radiated by the transmitting and receiving antennas in the backpropagation imaging algorithm. This method exploits the directive pattern of the antennas to reduce the level of grating lobes in SAR images.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Chemistry, Analytical
Yuri Alvarez Lopez, Fernando Las-Heras Andres
Summary: Fourier-based imaging, along with backpropagation algorithms such as delay-and-sum, is widely used in microwave imaging due to its computational efficiency and maintained image resolution. This paper presents a modified version of the Fourier-based algorithm that takes into account the radiation field of the Tx/Rx antennas of the microwave imaging system, aiming to improve accuracy. The impact on the imaged targets is analyzed quantitatively and qualitatively, with performance compared to other aliasing mitigation methods in subsampled microwave imaging scenarios.
Article
Engineering, Electrical & Electronic
Alicia Florez Berdasco, Jaime Laviada, Maria Elena de Cos Gomez, Fernando Las-Heras
Summary: The aim of this article is to evaluate the limitations of wearable antennas in different collision avoidance scenarios for visually impaired individuals. The analysis examines the use of medium distance obstacle detection and short distance imaging techniques utilizing synthetic aperture radar (SAR). Different measurements are conducted to assess the performance of the antennas and identify their main limitations in various test scenarios.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Engineering, Electrical & Electronic
Jaime Laviada, Guillermo Alvarez-Narciandi, Fernando Las-Heras
Summary: This work presents an approach to enhance the quality of SAR images by applying a deep learning method called cGAN. The cGAN can detect and remove artifacts, effectively improving the image quality. Compared to conventional methods, this approach has more stable training and better performance.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2022)
Proceedings Paper
Remote Sensing
Guillermo Alvarez-Narciandi, Jaime Laviada, Fernando Las-Heras
Summary: This paper presents a portable freehand millimeter-wave imaging system based on a highly integrated radaron-chip module. The system offers high flexibility, scanning speed, and cost-effectiveness for imaging in situations where large scanners are not practical or affordable. Through synthetic aperture radar processing techniques, the system achieves high-resolution image acquisition. The imaging system outperforms compact imagers based on lower integration level radiofrequency front-ends in terms of image quality.
PASSIVE AND ACTIVE MILLIMETER-WAVE IMAGING XXV
(2022)
Proceedings Paper
Engineering, Mechanical
M. Garcia-Fernandez, G. Alvarez-Narciandi, Y. Alvarez-Lopez, F. Las-Heras
Summary: This article analyzes the performance of a Ground Penetrating Radar (GPR) system mounted on an Unmanned Aerial Vehicle (UAV). The system is designed to safely, quickly, and autonomously inspect the subsoil to detect buried landmines and Improvised Explosive Devices (IEDs). By integrating highly-accurate positioning sensors and using a Synthetic Aperture Radar (SAR) algorithm, the radar measurements are combined to produce 3D high-resolution radar images of the subsurface. Extensive testing of prototypes and different GPR architectures in realistic scenarios has shown that a high probability of detection can be achieved for targets with a diameter larger than 10 cm, regardless of metallic or non-metallic composition, even under challenging operational conditions. The proposed clutter mitigation techniques are essential in achieving such high detection capabilities, particularly for low-metal content devices, and allow for automatic target recognition.
CHEMICAL, BIOLOGICAL, RADIOLOGICAL, NUCLEAR, AND EXPLOSIVES (CBRNE) SENSING XXIII
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Guillermo Alvarez-Narciandi, Jaime Laviada, Fernando Las-Heras
Summary: This article assesses the impact of the number of transmitting and receiving channels on the image quality of a freehand millimeter-wave imaging system. The results show that the higher the number of channels considered, the better the image quality. However, accurate target reconstruction can still be achieved with a reduced number of channels, reducing computational cost and increasing acquisition speed.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
O. Breinbjerg, J. M. Bjorstorp, T. M. Gemmer, A. C. Granich, F. Las-Heras, M. Rodriguez-Pino, M. Sierra Castaner, X. Sun, P. Ratajczak, L. Le Coq, R. Vallauri, A. Vicentini, H. Garcia Lopez del Amo, D. Allenic, L. Rolo, I Barbary, M. Saporetti, R. Tena Sanchez, C. Hunscher, J. Herrero del Real
Summary: This paper presents a campaign conducted by ESA and EurAAP to compare antenna measurement facilities, involving 12 European institutions and a total of 13 measurement facilities. The DTU-ESA mm-VAST antenna was used for the measurements, and the results will be published separately.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
M. E. de Cos Gomez, H. Fernandez Alvarez, F. Las-Heras Andres
Summary: This study presents a compact and low-cost 1x10 array antenna on polypropylene (PP) for wearable 24GHz radar applications. The electromagnetic characterization of the eco-friendly PP substrate is performed, and the performance of the antenna is optimized and tested. The results show that the proposed array antenna achieves improved performance compared to existing 24GHz antennas.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
A. Florez Berdasco, M. E. de Cos Gomez, H. Fernandez Alvarez, F. Las-Heras Andres
Summary: An uniplanar compact array-HIS antenna suitable for imaging in the ISM mmWave frequency band is proposed, with the intended application of supporting blind people with a collision avoidance system. Various arrangements of the HIS unit cells are considered to enhance radiation parameters, comparing the achievements with state of the art antennas at 24 GHz.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Maria Garcia-Fernandez, Guillermo Alvarez-Narciandi, Yuri Alvarez Lopez, Fernando Las-Heras Andres
Summary: This contribution presents the objectives and achievements of the SAFEDRONE project, which focuses on developing UAV-based high-resolution Ground Penetrating Radar systems for detecting buried landmines and IEDs. The project tests different architectures and integrates precise positioning and geo-referring subsystems, enabling fast scanning and high-accuracy radar imaging using UAVs.
2022 16TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP)
(2022)
