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Karim Achouri

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Related publications (51)

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

Surface Susceptibilities as Characteristic Models of Reflective Metasurfaces

Karim Achouri, Shourya Dutta Gupta, Ville Tuovi Tiukuvaara

While metasurfaces (MSs) are constructed from deeply subwavelength unit cells, they are generally electrically large and full-wave simulations of the complete structure are computationally expensive. Thus, to reduce this high computational cost, nonuniform ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

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

Multipolar expansions for scattering and optical force calculations beyond the long wavelength approximation

Olivier Martin, Karim Achouri, Andrei Kiselev, Marco Riccardi

We review three different approaches for the calculation of electromagnetic multipoles, namely, the Cartesian primitive multipoles, the Cartesian irreducible multipoles, and the spherical multipoles. We identify the latter as the best suited to describe th ...

AMER PHYSICAL SOC2022

Reciprocal Metasurfaces for On-axis Reflective Optical Computing

Karim Achouri, Romain Christophe Rémy Fleury, 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

Perfect gradient metasurfaces are not the most efficient

Olivier Martin, Karim Achouri, Hsiang-Chu Wang

Metasurfaces rely on the resonances of nanostructures with dimensions in the nanometer range for devices working in the visible regime. The corresponding fabrication technology requires E-beam exposure and can be quite challenging. It is prone to defects a ...

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

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

Multipolar origin of electromagnetic transverse force resulting from TE/TM wave interference

Olivier Martin, Karim Achouri, Andrei Kiselev

In this paper, we aim at unveiling the underlying physical mechanism for transversal optical forces, appearing due to the simultaneous illumination of a spherical object with two plane waves possessing different polarizations. The appearance of such a tran ...

2021

Dynamics of optical forces and torques in plasmonic systems: a surface integral equation

Olivier Martin, Karim Achouri, Andrei Kiselev

A novel approach is introduced to determine the time evolution of optical forces and torques on arbitrary shape nanostructures by combining Maxwell's stress tensor with the surface integral equation method (SIE). Conventional time averaging of Maxwell’s st ...

SPIEDigitalLibrary2020

Angular Scattering Properties of Metasurfaces

Olivier Martin, Karim Achouri

This article aims at studying the angular scattering properties of bianisotropic metasurfaces and clarifying the different roles played by tangential and normal polarization densities. Different types of metasurfaces are considered for this study and are c ...

2020

Limitations of the Metasurface Diluted-Slab Model

Christophe Caloz, Karim Achouri

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

Robustness analysis of metasurfaces

Olivier Martin, Karim Achouri, Hsiang-Chu Wang

2020

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

Multipolar origin of electromagnetic transverse force resulting from two-wave interference

Olivier Martin, Karim Achouri, Andrei Kiselev

We propose a theoretical study on the electromagnetic forces resulting from the superposition of TE and TM plane waves interacting with a sphere. Specifically, we first show that, under such an illumination condition, the sphere is subjected to a force tra ...

AMER PHYSICAL SOC2020

Nonlinear metasurfaces for tailoring second-harmonic generation

Olivier Martin, Karim Achouri

2019

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

Parallel integro-differential equation solving via multi-channel reciprocal bianisotropic metasurface augmented by normal susceptibilities

Karim Achouri, Ali Momeni

Analog optical signal processing has dramatically transcended the speed and energy limitations accompanied with its digital microelectronic counterparts. Motivated by recent metasurface?s evolution, the angular scattering diversity of a reciprocal passive ...

2019

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

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