642 citations · 1.9k across the 40 of their papers we have counts for
45 papers
Electromagnetic Theory of Metasurface Perfect Magnetic Conductor (PMC)
Oscar Céspedes Vicente, Karim Achouri, Christophe Caloz
Artificial magnetic conductors (AMCs) mimic the idealized boundary condition of a perfect magnetic conductor (PMC), which reflects electromagnetic waves with a preserved electric f…
Multipolar Angular Scattering of Substrated Metasurfaces
Hossein Allahverdizadeh, Karim Achouri
Properly modeling and predicting the scattering response of a metasurface is a particularly challenging task. This has been shown to be especially difficult if the metasurface supp…
A General Expression for Homogeneous Metasurface Scattering
Francisco S. Cuesta, Karim Achouri
The general approach in metasurface design is to find the unit-cell properties required to achieve a given functionality. This is usually done by modeling the metasurface as a comb…
Angle-Invariant Scattering in Metasurfaces
Mustafa Yücel, Francisco S. Cuesta, Karim Achouri
Metasurfaces are efficient and versatile electromagnetic structures that have already enabled the implementation of a wide range of microwave and photonic wave shaping applications…
Step Function in Momentum Space by a Metagrating
Mahmoud A. A. Abouelatta, Sergejs Boroviks, Olivier J. F. Martin +1
Metasurface research has shown significant potential for controlling the polarization, amplitude, phase and propagation direction of light. Nevertheless, control over the angular r…
Minireview on Disordered Optical Metasurfaces
P. Lalanne, A. Dmitriev, C. Rockstuhl +2
The use of coherent wave phenomena to enhance device performance is a cornerstone of modern optics. In juxtaposition to (locally) periodic metasurfaces, their disordered counterpar…
The art of finding the optimal scattering center(s)
Alexander V. Kildishev, Karim Achouri, Daria Smirnova
The efficient use of a multipole expansion of the far field for rapid numerical modeling and optimization of the optical response from ordered and disordered arrays of various stru…
Multipolar Pseudochirality Induced Optical Torque
Karim Achouri, Mintae Chung, Andrei Kiselev +1
It has been observed that achiral nano-particles, such as flat helices, may be subjected to an optical torque even when illuminated by normally incident linearly polarized light. H…
Quadrupolar susceptibility modeling of substrated metasurfaces with application to the generalized Brewster effect
Ville Tiukuvaara, Olivier J. F. Martin, Karim Achouri
We derive generalized sheet transition conditions (GSTCs) including dipoles and quadrupoles, using generalized functions (distributions). This derivation verifies that the GSTCs ar…
Demonstration of a plasmonic nonlinear pseudo-diode
Sergejs Boroviks, Andrei Kiselev, Karim Achouri +1
We demonstrate a nonlinear plasmonic metasurface that exhibits strongly asymmetric second-harmonic generation: nonlinear scattering is efficient upon excitation in one direction an…
Spatial Symmetries in Multipolar Metasurfaces: From Asymmetric Angular Transmittance to Multipolar Extrinsic Chirality
Karim Achouri, Ville Tiukuvaara, Olivier J. F. Martin
We propose a framework that connects the spatial symmetries of a metasurface to its material parameter tensors and its scattering matrix. This provides a simple yet effective way t…
Multipolar expansions for scattering and optical force calculations beyond the long wavelength approximation
Marco Riccardi, Andrei Kiselev, Karim Achouri +1
We review three different approaches for the calculation of electromagnetic multipoles, namely the Cartesian primitive multipoles, the Cartesian irreducible multipoles and the sphe…
Crossing of the branch cut: the topological origin of a universal 2π-phase retardation in non-Hermitian metasurfaces
Rémi Colom, Elena Mikheeva, Karim Achouri +5
Full wavefront control by photonic components requires that the spatial phase modulation on an incoming optical beam ranges from 0 to 2π. Because of their radiative coupling to the…
Surface Susceptibilities as Compact Full-Wave Simulation Models of Fully-Reflective Volumetric Metasurfaces
Ville Tiukuvaara, Tom. J. Smy, Karim Achouri +1
While metasurfaces (MSs) are constructed from deeply-subwavelength unit cells, they are generally electrically large and full-wave simulations of the complete structure are computa…
Multipolar Modeling of Spatially Dispersive Metasurfaces
Karim Achouri, Olivier J. F. Martin
There is today a growing need to accurately model the angular scattering response of metasurfaces for optical analog processing applications. However, the current metasurface model…
Extension of Lorentz Reciprocity and Poynting Theorems for Spatially Dispersive Media with Quadrupolar Responses
Karim Achouri, Olivier J. F. Martin
We provide a self-consistent extension of the Lorentz reciprocity theorem and the Poynting theorem for media possessing electric and magnetic dipolar and quadrupolar responses rela…
Reciprocal Metasurfaces for On-axis Reflective Optical Computing
Ali Momeni, Hamid Rajabalipanah, Mahdi Rahmanzadeh +4
Analog computing has emerged as a promising candidate for real-time and parallel continuous data processing. This paper presents a reciprocal way for realizing asymmetric optical t…
Fundamental Properties and Classification of Polarization Converting Bianisotropic Metasurfaces
Karim Achouri, Olivier J. F. Martin
We provide a detailed discussion on the electromagnetic modeling and classification of polarization converting bianisotropic metasurfaces. To do so, we first present a general appr…
Multipolar Origin of the Unexpected Transverse Force Resulting from Two-Wave Interference
Karim Achouri, Andrei Kiselev, Olivier J. F. Martin
We propose a theoretical study on the electromagnetic forces resulting from the superposition of a TE and TM plane waves interacting with a sphere. Specifically, we first show that…
Metasurface Modeling by a Thin Slab
Mojtaba Dehmollaian, Yousef Vahabzadeh, Karim Achouri +1
We investigate the possibility to model a metasurface, defined as a zero-thickness sheet of surface polarization currents, by a thin slab, characterized by a subwavelength thicknes…
Generalized Optical Signal Processing Based on Multi-Operator Metasurfaces Synthesized by Susceptibility Tensors
Ali Momeni, Hamid Rajabalipanah, Ali Abdolali +1
This paper theoretically proposes a multichannel functional metasurface computer characterized by Generalized Sheet Transition Conditions (GSTCs) and surface susceptibility tensors…
Influence of Reciprocity, Symmetry and Normal Polarizations on the Angular Scattering Properties of Bianisotropic Metasurfaces
Karim Achouri, Olivier J. F. Martin
This paper aims at studying the angular scattering properties of bianisotropic metasurfaces and at clarifying the different roles played by tangential and normal polarization densi…
Surface-Wave Dispersion Retrieval Method and Synthesis Technique for Bianisotropic Metasurfaces
Karim Achouri, Olivier J. F. Martin
We propose a surface-wave dispersion retrieval method and synthesis technique that applies to bianisotropic metasurfaces that are embedded in symmetric or asymmetric environments.…
What is Nonreciprocity?
Christophe Caloz, Andrea Alù, Sergei Tretyakov +3
This paper aims at providing a global perspective on electromagnetic nonreciprocity and clarifying confusions that arose in the recent developments of the field. It provides a gene…