Prof. Zouheir Sekkat Profile

Prof. Zouheir Sekkat

at MAScIR-UM6P

SPIE Involvement:

Conference Chair | Track Chair | Editor | Author

Publications (30)

Proceedings Article | 3 October 2022 Presentation

Model for athermal enhancement of molecular mobility in solid polymers by light (Conference Presentation)

Zouheir Sekkat

Proceedings Volume PC12212, PC1221209 (2022) https://doi.org/10.1117/12.2636119

KEYWORDS: Polymers, Solids, Motion models, Absorption, Glasses, Temperature metrology

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Proceedings Article | 1 June 2022 Paper

Thin film sensing by metal-insulator-metal plasmonic structures

S. Refki, Y. Elidrissi, N. Andam, S. Hayashi, Z. Sekkat

Proceedings Volume 12145, 1214504 (2022) https://doi.org/10.1117/12.2622229

KEYWORDS: Sensors, Polymethylmethacrylate, Silver, Thin films, Reflectivity, Refractive index, Plasmonics, Molecules, Electric field sensors, Surface plasmons

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Proceedings Article | 1 August 2021 Poster

Enhancement of molecular orientation by surface enhanced visible absorption of dye molecules in the vicinity of gold nano-antennas

Zouheir Sekkat, Siham Refki, Sanaa Elhani

Proceedings Volume 11812, 118120I (2021) https://doi.org/10.1117/12.2595343

KEYWORDS: Absorption, Gold, Molecules, Signal detection, Nanoantennas, Signal attenuation, Polymers, Polymer thin films, Plasmonics, Mass attenuation coefficient

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Proceedings Article | 1 August 2021 Poster

Voxels optimization in 3D laser nanoprinting

Zouheir Sekkat, Yahya Bougdid

Proceedings Volume 11812, 118120K (2021) https://doi.org/10.1117/12.2595346

KEYWORDS: Nonimpact printing, Nanolithography, Diffraction, Absorption

Proceedings Article | 1 August 2021 Poster

Optical characterization of ultra-thin films of dye doped polymers using ellipsometry and surface plasmon spectroscopy

Zouheir Sekkat, Najat Andam, Siham Refki

Proceedings Volume 11812, 118120J (2021) https://doi.org/10.1117/12.2595344

KEYWORDS: Spectroscopy, Surface plasmons, Polymers, Ellipsometry, Refractive index, UV-Vis spectroscopy, Thin films, Spectroscopic ellipsometry, Photonics, Imaging spectroscopy

Proceedings Article | 25 August 2020 Poster

Efficient formation of holographic gratings by gold nanoparticles dispersed on azo doped polymer films

Ibrahim Boudene, Siham Refki, Zouheir Sekkat

Proceedings Volume 11477, 114770M (2020) https://doi.org/10.1117/12.2567976

KEYWORDS: Gold, Nanoparticles, Holography, Polymers, Polymer thin films, Diffraction gratings, Switches, Photosensitive materials, Biomedical optics, Diffraction

Proceedings Article | 25 August 2020 Poster + Paper

Study the effect of fullerene derivatives ratio on P3HT-based inverted organic solar cells

I. Anefnaf, S. Aazou, G. Schmerber, A. Dinia, Z. Sekkat

Proceedings Volume 11474, 114741P (2020) https://doi.org/10.1117/12.2568790

KEYWORDS: Fullerenes, Organic photovoltaics, Solar cells, Atomic force microscopy, Scanning electron microscopy, Measurement devices, External quantum efficiency, Absorption, Thin films, Raman spectroscopy

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Proceedings Article | 10 September 2019 Presentation

Light-activating materials by molecular machines (Conference Presentation)

Zouheir Sekkat

Proceedings Volume 11098, 1109808 (2019) https://doi.org/10.1117/12.2528139

KEYWORDS: Molecular machines, Particles, Polarization

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Proceedings Article | 30 August 2019 Paper

Photochemical tweezing and surface relief gratings in azo-polymers

Sara Moujdi, Zouheir Sekkat

Proceedings Volume 11098, 110980Q (2019) https://doi.org/10.1117/12.2529522

KEYWORDS: Polarization, Modulation, Particles, Polymers, Molecules, Atomic force microscopy, Holography, Diffraction gratings, Diffraction, Chromophores

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Proceedings Article | 30 August 2019 Presentation + Paper

Direct laser writing of submicrometric voxels in two-photon photopolymerization

Yahya Bougdid, Youssef El Idrissi, Imad Maouli, Zouheir Sekkat

Proceedings Volume 11098, 110980G (2019) https://doi.org/10.1117/12.2528439

KEYWORDS: Polymers, Polymerization, Nanofabrication, Nanofibers, Femtosecond phenomena, Scanning electron microscopy, Nanolithography, Multiphoton lithography, 3D modeling, Absorption

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Proceedings Article | 1 March 2019 Paper

Azo-polymers for holographic recording: photo-assisted holography and surface relief gratings

S. Moujdi, Y. Bougdid, A. Rahmouni, T. Mahfoud, D. Nesterenko, M. Halim, Z. Sekkat

Proceedings Volume 10944, 1094403 (2019) https://doi.org/10.1117/12.2513416

KEYWORDS: Polarization, Holography, Polymers, Diffraction, Modulation, Holograms, Refractive index, Diffraction gratings, Atomic force microscopy

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Proceedings Article | 19 September 2018 Presentation + Paper

Plasmonic coupled modes in metal-insulator-metal structures for sensing applications

N. Andam, S. Refki, S. Hayasi, A. Rahmouni, H. Ishitobi, D. Nesterenko, Y. Inouye, Z. Sekkat

Proceedings Volume 10722, 107220O (2018) https://doi.org/10.1117/12.2319936

KEYWORDS: Sensors, Gold, Glucose, Plasmonics, Photonics, Interfaces, Surface plasmons, Reflectivity, Structural sensing, Metals

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Proceedings Article | 14 September 2018 Paper

Motion of matter induced by light fueled molecular machines

Sanaa Elhani, Zouheir Sekkat

Proceedings Volume 10740, 1074007 (2018) https://doi.org/10.1117/12.2319307

KEYWORDS: Polymers, Particles, Molecules, Molecular machines, Polarization, Optical tweezers, Absorption, Optical manipulation, Atomic force microscopy, Laser applications

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Proceedings Article | 14 September 2018 Paper

Laser nanofabrication in photoresists by two-photon absorption

Yahya Bougdid, Imad Maouli, Anouar Rahmouni, Kentaro Mochizuki, Mohammed Halim, Zouheir Sekkat

Proceedings Volume 10740, 107400G (2018) https://doi.org/10.1117/12.2322373

KEYWORDS: Polymers, Absorption, Scanning electron microscopy, Femtosecond phenomena, Glasses, Polymerization, Spatial resolution, Nanofabrication, Two photon polymerization, Photoresist materials

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Proceedings Article | 14 September 2018 Paper

On surface relief gratings in azo-polymers

S. Moujdi, A. Rahmouni, T. Mahfoud, D. Nesterenko, M. Halim, Z. Sekkat

Proceedings Volume 10740, 107400A (2018) https://doi.org/10.1117/12.2320625

KEYWORDS: Polarization, Polymers, Diffraction gratings, Diffraction, Atomic force microscopy, Holography, Motion models, Polymer thin films, Refractive index, Photonics

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Proceedings Article | 24 April 2018 Paper

Light-fueled molecular machines can move matter

Sara Moujdi, Zouheir Sekkat

Proceedings Volume 10712, 107120G (2018) https://doi.org/10.1117/12.2318935

KEYWORDS: Polymers, Polarization, Molecular machines, Photons, Optical manipulation

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Proceedings Article | 10 November 2016 Presentation

Optical tweezing by photochemistry (Conference Presentation)

Zouheir Sekkat, Satoshi Kawata, Yasushi Inouye, Hidekazu Ishitobi

Proceedings Volume 9922, 99221M (2016) https://doi.org/10.1117/12.2236628

KEYWORDS: Optical trapping, Photochemistry, Optical manipulation, Optical tweezers, Diffusion, Optical micromanipulation, Current controlled current source

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Proceedings Article | 9 November 2016 Presentation

Fano resonances arising from coupled surface plasmon polariton and waveguide modes (Conference Presentation)

Zouheir Sekkat, Shinji Hayashi, Dmitry Nesterenko, Anouar Rahmouni, Hidekazu Ishitobi, Yasushi Inouye, Satoshi Kawata

Proceedings Volume 9921, 99210K (2016) https://doi.org/10.1117/12.2236682

KEYWORDS: Surface plasmon polaritons, Waveguide modes, Planar waveguides, Electromagnetism, Plasmonics, Scientific research, Current controlled current source

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Proceedings Article | 3 November 2016 Presentation

On the theory of photomigration (Conference Presentation)

Zouheir Sekkat, Satoshi Kawata, Hidekazu Ishitobi, Yasushi Inouye

Proceedings Volume 9939, 993908 (2016) https://doi.org/10.1117/12.2236623

KEYWORDS: Polymers, Optical manipulation, Optical trapping, Polarization, Scientific research, Organic materials, Current controlled current source

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Proceedings Article | 8 September 2011 Open Access

Single-, two-, and multi-photon driven molecular motion and nanopatterning in azo-polymer films

Zouheir Sekkat, Hidekazu Ishitobi, Mamoru Tanabe, Tsunemi Hiramatsu, Satoshi Kawata

Proceedings Volume 8113, 81130N (2011) https://doi.org/10.1117/12.890511

KEYWORDS: Polymers, Polarization, Polymer thin films, Atomic force microscopy, Near field, Near field optics, Diffraction, Absorption, Optical lithography, Glasses

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We review our work on nanopatterning in azo-polymer films by single, two- and multi-phopton driven molecular motion in solid bulk polymer. It is now known that light induced molecular movement occurs below the polymer glass transition temperature by chromophores photoisomerization via either linear or nonlinear absorption, and in this paper we will show that nanoscale polymer movement is induced by a tightly focused laser beam in an azo-polymer film just at the diffraction limit of light. The deformation pattern which is produced by photoisomerization of the azo dye is strongly dependent on the incident laser polarization and the longitudinal focus position of the laser beam along the optical axis. The anisotropic nanofluidity of the polymer film and the optical gradient force played important roles in the light induced polymer movement. We explored the limits of the size of the photo-induced deformation, and we found that the deformation depends on the laser intensity and the exposure time. The smallest deformation size achieved was 200 nm in full width of half maximum; a value which is nearly equal to the size of the diffraction limited laser spot. Furthermore, a nano protrusion was optically induced on the surface of the films, beyond the limit of light diffraction, by metal tip enhanced near-filed illumination. A silver coated tip was located inside the diffraction limited spot of a focused laser beam (460 nm), and an enhanced near-field, with 30 nm light spot, was generated in the vicinity of the tip due to localized surface plasmons. The incident light intensity was carefully regulated to induce surface nanodeformation by such a near-field spot. A nano protrusion with 47 nm full width of half maximum and 7 nm height was induced. The protrusion occurs because the film is attracted towards the tip end during irradiation. At the top of the protrusion, an anisotropic nanomovement of the polymer occurs in a direction nearly parallel to the polarization of the incident light, and suggests the existence at the tip end of not only a longitudinal, i.e., along the tip long axis, but also a lateral component of the electric field of light. The azo-polymer film helps map the electric field in the close vicinity of the tip. We also report on two-photon patterning of the films. Exposure of azo polymer films, which absorb in the visible range (λ_max = 480 nm), to intense 920 nm irradiation leads to polarization dependent patterning which are associated with polymer nanomovement caused by photoselective two-photon cis ↔ trans isomerization, while irradiation at 780 nm induces multi-photon bleaching of the azo chromophore. These wavelengths hit bleaching and isomerization pathways in the chromophore, respectively.

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Proceedings Article | 4 September 2008 Paper

Light-induced accumulation of single-wall carbon nanotubes dispersed in aqueous solution

Satoru Shoji, Thomas Roders, Zouheir Sekkat, Satoshi Kawata

Proceedings Volume 7037, 70370O (2008) https://doi.org/10.1117/12.795675

KEYWORDS: Raman spectroscopy, Raman scattering, Carbon nanotubes, Objectives, Dielectrics, Light scattering, Helium neon lasers, Confocal microscopy, Laser scattering, Scattering

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Proceedings Article | 18 August 2005 Paper

Molecular orientation by two-photon absorption

H. Ishitobi, M. Maeda, Z. Sekkat, S. Kawata

Proceedings Volume 5935, 59350F (2005) https://doi.org/10.1117/12.611185

KEYWORDS: Absorbance, Absorption, Polarization, Chromophores, Polymethylmethacrylate, Anisotropy, Microscopes, Ultraviolet radiation, Visible radiation, Laser beam diagnostics

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Proceedings Article | 29 November 2000 Paper

Photo-orientation movement of photoisomerizable chromophores: quantifying analytical theory and application to spectrally overlapping and distinguishable isomers

Zouheir Sekkat, Hidekazu Ishitobi, Daisuke Yasumatsu, Satoshi Kawata

Proceedings Volume 4106, (2000) https://doi.org/10.1117/12.408499

KEYWORDS: Chromophores, Polymers, Ultraviolet radiation, Surface plasmons, Absorbance, Anisotropy, Polymethylmethacrylate, Visible radiation, Absorption, Nonlinear optics

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Proceedings Article | 22 September 1999 Paper

Near-field scanning optical microscope using a metallized cantilever tip for nanospectroscopy

Yasushi Inouye, Norihiko Hayazawa, Koji Hayashi, Zouheir Sekkat, Satoshi Kawata

Proceedings Volume 3791, (1999) https://doi.org/10.1117/12.363860

KEYWORDS: Near field scanning optical microscopy, Luminescence, Raman scattering, Near field, Light scattering, Stray light, Photons, Near field optics, Objectives, Rhodamine

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Proceedings Article | 7 May 1999 Paper

Optically oriented isomers of diarylethene and spiropyran in polymeric thin films

Hidekazu Ishitobi, Zouheir Sekkat, Satoshi Kawata

Proceedings Volume 3740, (1999) https://doi.org/10.1117/12.347740

KEYWORDS: Chromophores, Ultraviolet radiation, Surface plasmons, Visible radiation, Polymer thin films, Near field optics, Polymers, Absorption, Anisotropy, Polarization

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Proceedings Article | 29 July 1997 Paper

Unification of azo-polymer systems by photo-induced molecular movement

Zouheir Sekkat, Andre Knoesen, Wolfgang Knoll, Robert Miller

Proceedings Volume 10290, 102900H (1997) https://doi.org/10.1117/12.279824

KEYWORDS: Polymers, Molecules, Nonlinear optics, Optical storage, Supramolecular assemblies, Silicon, Oxides, Connectors

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Proceedings Article | 23 January 1997 Paper

Photosensitive organized organic films in the light of bound electromagnetic waves

Zouheir Sekkat, Wolfgang Knoll

Proceedings Volume 2998, (1997) https://doi.org/10.1117/12.264179

KEYWORDS: Ultraviolet radiation, Molecules, Polymers, Polarization, Anisotropy, Absorption, Dichroic materials, Refractive index, Reflectivity, Polymer thin films

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This paper describes recent advances in the field of photochromic polymeric structures for optical data storage. In particular, we discuss photo-induced effects in supramolecular assemblies containing azobenzene molecules (e.g. Langmuir-Blodgett-Kuhn structures and ultrathin silane layers). Reorientation of azobenzenes in these structures is compared to that observed in spin-cast films. Photoisomerization and photo-induced orientation of azobenzene molecules is studied at the molecular level by means of azosilane molecules chemisorbed on silicon oxide substrates. The study of the thermal back isomerization reaction of the azobenzene molecules in these layers reveals steric hindrance at the molecular level. These ultra-thin photochromic self-assembled monolayers (SAMs) exhibit persistent dichroism upon linearly polarized light irradiation. This dichroism could be both written and erased by irradiation with light of an appropriate wavelength. In addition, the sign of this dichroism can be inverted by choosing the appropriate polarization of the irradiating light, thus showing a 'smart communication' between the light polarization and the ultra-thin photochromic layers. Photoisomerization also induces reversible changes in the optical thickness of these molecularly thin SAMs. Langmuir- Blodgett-Kuhn (LBK) multilayer assemblies of 'hairy-rod' polyglutamates with stiff main chains and flexible side chains containing photochromic azo units exhibit a highly optically anisotropic structure when the azo molecules are in the trans form, and a nearly optically isotropic structure when the azo molecules are in the cis form. The trans $ARLR cis photoisomerization of the azo molecules switches them between a highly oriented trans configuration and a bend cis configuration, thus turning the anisotropy 'on' and 'off.' In contrast to spin-cast polymer films containing azobenzene units, photoselection under polarized light irradiation does not occur in these LBK structures. The study of the electronic density distribution of these films show that a remarkable variation in the LBK structures' stability comes with a seemingly small change in the side-chain structure. All the structures described here, form thin films that can be very sensitively characterized, by using surface plasmons and guided optical waves as electromagnetic modes bound to an interface.

Proceedings Article | 20 January 1994 Paper

Orientational manipulation of chromophores through photoisomerization

Michel Dumont, Sophie Hosotte, G. Froc, Zouheir Sekkat

Proceedings Volume 2042, (1994) https://doi.org/10.1117/12.166297

KEYWORDS: Molecules, Anisotropy, Chromophores, Optical pumping, Absorption, Hole burning spectroscopy, Polymers, Polarization, Diffusion, Polymer thin films

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Proceedings Article | 14 January 1993 Paper

Dynamical study of photoinduced anisotropy and orientational relaxation of azo dyes in polymeric films: poling at room temperature

Michel Dumont, Zouheir Sekkat

Proceedings Volume 1774, (1993) https://doi.org/10.1117/12.139169

KEYWORDS: Molecules, Anisotropy, Polymers, Optical pumping, Polymer thin films, Electro optics, Polymethylmethacrylate, Photopolymers, Dichroic materials, Modulation

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