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Karim Achouri

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Related publications (51)

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Fundamental Properties and Classification of Polarization Converting Bianisotropic Metasurfaces

Olivier Martin, Karim Achouri

We provide a detailed discussion on the electromagnetic modeling and classification of polarization converting bianisotropic metasurfaces. To do so, we first present a general approach to compute the scattering response of suchmetasurfaces, which relies on ...

2021

Extension of Lorentz reciprocity and Poynting theorems for spatially dispersive media with quadrupolar responses

Olivier Martin, Karim Achouri

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 related to electric and magnetic fields and field gradients thus corresponding t ...

AMER PHYSICAL SOC2021

Modeling of second-order nonlinear metasurfaces

Olivier Martin, Karim Achouri, Andrei Kiselev

We present a frequency-domain modeling technique for second-order nonlinear metasurfaces. The technique is derived from the generalized sheet transition conditions (GSTCs), which have been so far mostly used for modeling linear metasurfaces. In this work, ...

IOP Publishing Ltd2022

Generalized Optical Signal Processing Based on Multioperator Metasurfaces Synthesized by Susceptibility Tensors

Karim Achouri, Ali Momeni

This paper theoretically proposes a multichannel nonlocal metasurface computer characterized by generalized sheet transition conditions (GSTCs) and surface susceptibility tensors. The study explores polarization- and angle-multiplexed metasurfaces enabling ...

American Physical Society (APS)2019

Symmetries and Angular Scattering Properties of Metasurfaces

Olivier Martin, Karim Achouri

We study the angular scattering behavior of bianisotropic metasurfaces and deduce relationships between the corresponding symmetrical angular scattering properties and the structural symmetries of their scattering particles. This may be of practical intere ...

IEEE2019

Homogenization and Scattering Analysis of Second-Order Nonlinear Metasurfaces

Olivier Martin, Jérémy Butet, Karim Achouri, Gabriel David Bernasconi

We present an extensive discussion on the homogenization and scattering analysis of second-order nonlinear metasurfaces. We use the generalized sheet transition conditions (GSTCs) in the frequency-domain to model the electromagnetic responses of nonlinear ...

IEEE2018

Angle-invariant scattering in metasurfaces

Mustafa Yücel, Karim Achouri, Francisco Sebastian Cuesta Soto

Metasurfaces are efficient and versatile electromagnetic structures that have already enabled the implementation of a wide range of microwave and photonic wave shaping applications. Despite the extensive research into metasurfaces, a rigorous and comprehen ...

American Physical Society (APS)2025

Optimal Poloidal Multipole Expansion Centres

Karim Achouri

Resonant optical response is one of the key effects in nanophotonic structures. The characterization of the fundamental resonance metrics, quality factor, electric or magnetic field localization, polarization, and chirality, is often built on a multipolar ...

IEEE Computer Society2024

Multipolar Pseudochirality-Induced Optical Torque

Olivier Martin, Karim Achouri, Andrei Kiselev, Mintae Chung

It has been observed that achiral nanoparticles, such as flat helices, may be subjected to an optical torque even when illuminated by normally incident linearly polarized light. However, the origin of this fascinating phenomenon has so far remained mostly ...

Amer Chemical Soc2023

Synthesis and Analysis of Linear and Nonlinear Bianisotropic Metasurfaces

Olivier Martin, Karim Achouri, Christophe Caloz

We present our recent progress pertaining to the synthesis and analysis of bianisotropic linear and nonlinear metasurfaces. These developments are based on the generalized sheet transition conditions (GSTCs), which provide a very complete and general metho ...

IEEE2018

Multipole interplay controls optical forces and ultra-directional scattering

Olivier Martin, Karim Achouri, Andrei Kiselev

We analyze the superposition of Cartesian multipoles to reveal the mechanisms underlying the origin of optical forces. We show that a multipolar decomposition approach significantly simplifies the analysis of this problem and leads to a very intuitive expl ...

2020

Asymmetric phase modulation of light with parity-symmetry broken metasurfaces

Karim Achouri

The design of wavefront-shaping devices is conventionally approached using real-frequency modeling. However, since these devices interact with light through radiative channels, they are by default non-Hermitian objects having complex eigenvalues (poles and ...

Optica Publishing Group2023

Demonstration of a Plasmonic Nonlinear Pseudodiode

Olivier Martin, Karim Achouri, Andrei Kiselev, Sergejs Boroviks

We demonstrate a nonlinear plasmonic metasurface that exhibits strongly asymmetric second-harmonic generation: nonlinear scattering is efficient upon excitation in one direction, and it is substantially suppressed when the excitation direction is reversed, ...

AMER CHEMICAL SOC2023

Limitations of the Metasurface Diluted-Slab Model

Karim Achouri, Christophe Caloz

In this article, we investigate the possibility to model a metasurface, defined as a zero-thickness sheet of surface polarization currents and described by generalized sheet transition conditions (GSTCs), by a thin slab with a subwavelength thickness and u ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Multipolar Modeling of Spatially Dispersive Metasurfaces

Olivier Martin, Karim Achouri, Ville Tuovi Tiukuvaara

There is today a growing need to accurately model the angular scattering response of metasurfaces for optical analog processing applications. However, the current metasurface modeling techniques are not well suited for such a task since they are limited to ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Surface-wave dispersion retrieval method and synthesis technique for bianisotropic metasurfaces

Olivier Martin, Karim Achouri

We propose a surface-wave dispersion retrieval method and synthesis technique that applies to bianisotropic metasurfaces that are embedded in symmetric or asymmetric environments. Specifically, we use general zero-thickness sheet transition conditions to r ...

2019

Reciprocal Metasurfaces for On-axis Reflective Optical Computing

Romain Christophe Rémy Fleury, Karim Achouri, Ali Momeni

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 transfer functions (OTFs) in the reflection side of the on-axis processing ch ...

2021

Study of the Angular Spectrum of a Bianisotropic Refractive Metasurface at a Dielectric Interface

Karim Achouri, Christophe Caloz

We present an initial study of the angular spectrum of a bianisotropic refractive metasurface at an interface between two dielectric media. In this study, we report on the existence of three distinct angular regions: a) a rotated transmission cone, b) a mo ...

IEEE2018

Modelling of nonlinear metasurfaces: Second-harmonic generation and Kerr effect

Olivier Martin, Karim Achouri

We present a nonlinear metasurface modelling frame- work based on the generalized sheet transition conditions (GSTC). It may be used to synthesize or analyse the scat- tering behavior of second- and third-order metasurfaces. We specifically study second-ha ...

2019

Explanation of Optical Force and Torque on Nanomotors as the Interplay of Huygens Sources

Olivier Martin, Karim Achouri, Mintae Chung

Being able to understand how optical forces emerge from the interaction of light with matter is paramount for controlling the motion of nanoparticles as well as powering nanomotors. The purpose of this work is to uncover the physical mechanisms at the orig ...

IEEE2022