GUIZAL Brahim
Organisme : Université Montpellier
Professeur
(HDR)
Brahim.Guizal
umontpellier.fr
Bureau: 27.0, Etg: 2, Bât: 21  Site : Campus Triolet
Administration Nationale: 
Administration Locale: Membre d'un pool d'experts
 Membre du conseil du laboratoire
 Responsable de formations
 Responsable de diplôme (M2)

Domaines de Recherche:  Physique/Physique mathématique

Dernieres productions scientifiques :


Giant Casimir Torque between Rotated Gratings and the θ = 0 Anomaly
Auteur(s): Antezza M., Chan Ho bun, Guizal B., Marachevskii V., Messina R., Wang Mingkang
(Article) Publié:
Physical Review Letters, vol. 124 p.013903 (2020)
Texte intégral en Openaccess :
Ref HAL: hal02431447_v1
PMID 31976735
DOI: 10.1103/PhysRevLett.124.013903
WoS: 000505997600005
Exporter : BibTex  endNote
1 Citation
Résumé: We study the Casimir torque between two metallic onedimensional gratings rotated by an angle θ with respect to each other. We find that, for infinitely extended gratings, the Casimir energy is anomalously discontinuous at θ 1⁄4 0, due to a critical zeroorder geometric transition between a 2D and a 1Dperiodic system. This transition is a peculiarity of the grating geometry and does not exist for intrinsically anisotropic materials. As a remarkable practical consequence, for finitesize gratings, the torque per area can reach extremely large values, increasing without bounds with the size of the system. We show that for finite gratings with only ten period repetitions, the maximum torque is already 60 times larger than the one predicted in the case of infinite gratings. These findings pave the way to the design of a contactless quantum vacuum torsional spring, with possible relevance to micro and nanomechanical devices.



Longrange Heat and Energy Transfer through Hyperbolic Materials
Auteur(s): Biehs SvendAge, Messina R., Guizal B., Antezza M., Benabdallah Philippe, Deshmukh R., Galfsky T., Menon V, Agarwal G. S.
Conférence invité: PIERS 2019 (Rome, IT, 20190620)
Ref HAL: hal02190887_v1
Exporter : BibTex  endNote
Résumé: Heat flux exchanged between two hot bodies at subwavelength separation distances can exceed the limitpredicted by the blackbody theory. However, this superPlanckian transfer is restricted to these separationdistances. Here we demonstrate the possible existence of a superPlanckian transfer at arbitrary large separationdistances if the interacting bodies are connected in the near field with weakly dissipating hyperbolic waveguides.This result opens the way to longdistance transport of nearfield thermal energy.



Coupling between nanoslits lattice modes and metalinsulatorgraphene cavity modes: a semianalytical model
Auteur(s): Guizal B., Edee Kofi, Ben rhouma Maha, Antezza M.
Conférence invité: METANANO 2019 (Saint Petersbourg, RU, 20190715)
Ref HAL: hal02188829_v1
Exporter : BibTex  endNote
Résumé: We present a semianalytical model of the resonance phenomena occurring in a hybrid system made of a 1D array of periodic subwavelength slits deposited on an insulator/graphene layer. We show that the spectral response of this hybrid system can be fully explained by a simple semianalytical model based on weak and strong couplings between two elementary subsystems.



Coupling between subwavelength nanoslits lattice modes and metalinsulatorgraphene cavity modes: A semianalytical model
Auteur(s): Edee Kofi, Benrhouma Maha, Antezza M., Fan Jonathan albert, Guizal B.
(Article) Publié:
Osa Continuum, vol. 2 p.12961309 (2019)
Ref HAL: hal02076490_v1
DOI: 10.1364/OSAC.2.001296
WoS: 000464918500025
Exporter : BibTex  endNote
1 Citation
Résumé: We present a semianalytical model of the resonance phenomena occurring in a hybrid system made of a 1D array of periodic subwavelength slits deposited on an insulator/graphene layer. We show that the spectral response of this hybrid system can be fully explained by a simple semianalytical model based on weak and strong couplings between two elementary subsystems. The first elementary subsystem consists of a 1D array of periodic subwavelength slits viewed as a homogeneous medium. In this medium lives a metalinsulatormetal lattice mode interacting with surface and cavity plasmon modes. A weak coupling with surface plasmon modes on both faces of the perforated metal film leads to a broadband spectrum while a strong coupling between this first subsystem and a second one made of a grapheneinsulatormetal gap leads to a narrow band spectrum. We provide a semianalytical model based on these two interactions thus allowing efficient access of the full spectrum of the hybrid system.



Casimir Forces between Silicon Gratings
Auteur(s): Chan Ho bun, Wang Mingkang, Tang Lu, Ng C. Y., Chan Che ting, Messina R., Guizal B., Antezza M., Crosse John alexander
Conférence invité: PIERS : Progress In Electromagnetics Research Symposium (Toyama, JP, 20180801)
Ref HAL: hal01864295_v1
Exporter : BibTex  endNote
Résumé: The Casimir force arises from the quantum fluctuations of the electromagnetic field. It leads to an attraction between electrically neutral bodies with a vacuum gap that be comes measureable at nanoscale separations. Under the trend of miniaturization, such quantum electrodynamical effects are expected to play an important role in nanomechanical devices. One remarkable property of the Casimir force is its nontrivial dependence on the shape of the in teracting bodies. Experiments using the corrugated surface of gratings have demonstrated the deviation of the Casimir force from the proximity force approximation. In these experiments, it was necessary to choose one of the bodies to be a sphere to circumvent alignment difficulties.Here, we present measurement of the Casimir force gradient between two microfabricated silicon beams, both of which contain rectangular corrugations. One of the beams acts as the forcesensing element. As it vibrates in a perpendicular magnetic field, a back electromotive force is generated and the corresponding change in the current is measured. The force gradient exerted on this beam is measured from the resonance frequency shift. The distance to the other beam is controlled using a comb actuator integrated on the same substrate, where electrostatic forces push the second beam towards the forcesensing beam. By using lithography to define the structures, they are aligned to allow the two gratings to interpenetrate when the separation between them is reduced. Our data shows a number of novel features, including strong deviations of the force gradient from the proximity force approximation and a nonzero, distanceindependent Casimir force over certain range of displacement.We will also discuss the design of a bridge to measure the difference in Casimir forces on two types of surfaces. By fabricating an additional sensing beam next to the original one and measuring their resonant frequency shifts simultaneously in the same experimental run, the difference in the Casimir force gradient of two different geometries can be compared.

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