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Dive into the research topics where Jean Dahdah is active.

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Featured researches published by Jean Dahdah.


Applied Physics Letters | 2010

Acousto-optically tunable lithium niobate photonic crystal

Nadège Courjal; Sarah Benchabane; Jean Dahdah; Gwenn Ulliac; Yannick Gruson; Vincent Laude

We report on an active two-dimensional lithium niobate photonic crystal (PhC) driven by stationary Rayleigh surface acoustic waves. The configuration relies on two interdigital transducers that modulate the refractive index through the acousto-optical effect. Highly efficient, compact acousto-optical PhCs with an active length of only 13 μm and a driving electrical power of 20 mW have been fabricated and characterized. Experiments show that an enhancement factor of the elasto-optical interaction of the order of 61 is obtained thanks to slow light effects in the PhC.


IEEE Transactions on Plasma Science | 2013

A Nonperturbative Electrooptic Sensor for in Situ Electric Discharge Characterization

Gwenaël Gaborit; Jean Dahdah; Frédéric Lecoche; Pierre Jarrige; Yann Gaeremynck; Eric Duraz; Lionel Duvillaret

Pulsed power and intense electric field now apply to a large variety of domains for which the need of in situ nonperturbative measurements remains a challenge. The main requirements that sensors should fulfill for that purpose are nonmetallic composition, small size, ultrawide bandwidth, compatibility with liquids and gases, possibility for remote measurements at long distances, true vectorial (field direction) time-domain measurements, capability of measuring electric fields up to the electric breakdown of air, and a large dynamic range. Obviously, all these requirements cannot be achieved by a unique sensor. However, most of them are fulfilled by pigtailed electrooptic (EO) sensors. In this paper, after recalling the principle of the EO effect and its use for electric field measurement, we deal with the measurement linearity and selectivity of the EO sensor. Associated with the nonperturbative behavior of the EO sensor, the measurement dynamics of EO sensors exceeds 100 dB. Furthermore, EO sensors present an intrinsic flat response from quasi d.c. (10 Hz) up to a few tens of gigahertz. Thanks to their composition of high dielectric strength materials and their optical pigtail, EO sensors are completely immune to the electromagnetic environment except on a very small volume (≅ 10 mm3) corresponding to the transducer element of the sensor. This leads to a very high spatial resolution. We finally illustrate the capabilities of this technology through in situ measurement of the electric discharge transients and vectors.


IEEE Transactions on Plasma Science | 2014

Single Shot and Vectorial Characterization of Intense Electric Field in Various Environments With Pigtailed Electrooptic Probe

Gwenaël Gaborit; Pierre Jarrige; Frédéric Lecoche; Jean Dahdah; Eric Duraz; C. Volat; Lionel Duvillaret

In this paper we illustrate the ability of electrooptic sensors to perform electric (E)-field vectorial measurements. Thanks to their frequency response spreading over nine decades and to their measurement dynamics reaching 120 dB, these sensors are of high interest for some applications (near field mapping, energy line monitoring, electromagnetic compatibility, and so on). Furthermore, due to their fully dielectric structure and millimetric size, almost no perturbation is induced on the E-field to be measured, even in the near field region. This paper is focused on high-intensity pulsed E-field characterization in different environments such as air, water (bioelectromagnetism applications), or plasmas (in situ assessment of the E-field associated to an electric discharge and to the induced plasma). The use of such a technology for electrical equipment and energy line monitoring is also investigated.


Journal of The Optical Society of America B-optical Physics | 2010

Analysis of a photonic crystal cavity based on absorbent layer for sensing applications

Jean Dahdah; Nadège Courjal; F. I. Baida

We present a photonic crystal (PhC) cavity based on a single hole defect filled with a sensitive absorbent layer for sensing applications. A preliminary study performed with the plane wave expansion method shows that the resonance peak of the cavity mode is 0.5 nm shifted for a 1 nm thickness variation of the sensitive layer. A Lorentz dispersion model implemented in a two-dimensional-finite difference time domain homemade code shows that the absorption of the layer can be exploited for enhancing the sensitivity of the sensor. With the proposed geometry, we find that a variation in the refractive index of 10−7 leads to a variation in the transmittivity of 23% at the resonance peak. This study is proposed for the development of a compact benzene sensor on a MgO doped lithium niobate PhC.


Optics Express | 2011

Optimization of LiNbO 3 photonic crystals: toward 3D LiNbO 3 micro-components

Nadège Courjal; Jean Dahdah; Gwenn Ulliac; Pierre Sevillano; Blandine Guichardaz; Fadi I. Baida

We report easy-to-implement techniques to improve the reflectivity of LiNbO₃ photonic crystals within the photonic bandgap. Firstly, we show that widening the channel waveguides confines the optical modes in the vertical direction, which leads to the development of the first 2D-PhCs on Ti-indiffused LiNbO₃ waveguides. We also report the first optical characterization of PhCs implemented on ridge LiNbO₃ waveguides. The reflectivity is measured using a swept-source optical coherence tomography (OCT) system, together with the transmission spectrum. Finally we report 3D-PhCs LiNbO₃ fabricated by Focused Ion Beam milling on the side of ridge waveguides.


Journal of Applied Physics | 2011

Near-field observations of light confinement in a two dimensional lithium niobate photonic crystal cavity

Jean Dahdah; Maria Pilar-Bernal; Nadège Courjal; Gwenn Ulliac; Fadi I. Baida

We report the characterization of a lithium niobate photonic crystal cavity using near field scanning optical microscopy (NSOM) operating in collection scanning mode. The cavity is implemented on an annealed proton exchange waveguide by focused ion beam milling. We observe a confinement of the optical field at the center of the cavity by analyzing the collected light with a probe positioned above the photonic structure. The experimental NSOM results obtained are compared to numerical results obtained by finite difference time domain method. A good agreement is obtained between theoretical and experimental results where a cavity mode appears around λ = 1540 nm.


IEEE Photonics Journal | 2012

Nanocoaxial Waveguide Grating as Quarter-Wave Plates in the Visible Range

Jean Dahdah; Jalaa Hoblos; Fadi I. Baida

A geometrical artificial anisotropy can be controlled through polarization and propagation properties of guided modes inside annular nanocavities with elliptical core. In this paper, we theoretically demonstrate the principle of obtaining this anisotropy by exploiting such guided modes. We present the control of this birefringence through an example of a quarter-wave plate exhibiting a transmission of about 83% in the visible range associated with a giant effective birefringence of around Δn = 0.75.


IEEE Photonics Technology Letters | 2014

Unbiased Electro-Optic Waveguide as a Sensitive Nuclear Magnetic Resonance Sensor

Reina Aydé; Gwenalël Gaborit; Jean Dahdah; Lionel Duvillaret; Nadège Courjal; Clément Guyot; Raphaël Sablong; Anne-Laure Perrier; Olivier Beuf

A pigtailed Ti:LiNbO3 waveguide is here associated to a specific nuclear magnetic resonant coil to perform a low invasive magnetic field measurement. The developed device exploits a passive electro-optic transduction between the measured magnetic field and polarization state modulation of a laser probe beam. Because of the use of integrated optics, the coil electromotive force induces a dramatically enhanced electric field, thus leading to sensitivity improvement. A minimum detectable magnetic field lower than 60 fT. Hz-1/2 is achieved at the resonant frequency of 128 MHz. A dynamic range exceeding 100 dB is experimentally demonstrated.


Optics Letters | 2014

Optical characterization of ultra-short Bragg grating on lithium niobate ridge waveguide

Clément Guyot; Gwenn Ulliac; Jean Dahdah; Wentao Qiu; Maria-Pilar Bernal; F. I. Baida; Nadège Courjal

In this Letter, we report a technique to etch giant aspect ratio nanostructures in lithium niobate. An 8 μm long Bragg grating on a Ti:LiNbO3 ridge waveguide was fabricated by combining optical-grade dicing and focused ion beam milling. The reflectivity was evaluated using an optical coherence tomography system: it is measured to be 53% for the TM wave and 47% for the TE wave. We study by 2D-FDTD the modeled behavior of the electromagnetic field when an angle exists between two consecutive sidewalls of the grating in order to understand the difference between ideal Bragg grating and experimental samples. These simulations allow us to optimize the parameters in order to increase the reflection of the grating up to 80%.


ieee international pulsed power conference | 2013

Single shot measurements of electric field vector in various environments with pigtailed electro-optic probes

Gwenaël Gaborit; Pierre Jarrige; Frédéric Lecoche; Jean Dahdah; Eric Duraz; Lionel Duvillaret; C. Volat

We here illustrate the ability of electro-optic sensors to perform electric field vectorial measurements. Thanks to their frequency response that remains flat over nine decades and to their measurement dynamics reaching 120 dB, these sensors are of key interest for many applications. Furthermore, due to their fully dielectric structure and to their millimetric size, almost no perturbation is induced on the electric field to be measured, even in the near field region. This paper is focused on high intensity pulsed electric field characterization in different environments such as water (bioelectromagnetism applications) or plasma (in-situ assessment of the electric-field associated to an electric discharge). The use of such technology for electrical equipments and energy lines monitoring is also investigated.

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Dive into the Jean Dahdah's collaboration.

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Lionel Duvillaret

Centre national de la recherche scientifique

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Nadège Courjal

University of Franche-Comté

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Gwenn Ulliac

University of Franche-Comté

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Gwenaël Gaborit

Centre national de la recherche scientifique

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Maria-Pilar Bernal

University of Franche-Comté

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Fadi I. Baida

Centre national de la recherche scientifique

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