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Bartual-Murgui C.,National Polytechnic Institute of Toulouse | Salmon L.,National Polytechnic Institute of Toulouse | Akou A.,National Polytechnic Institute of Toulouse | Thibault C.,Hoffmann-La Roche | And 7 more authors.
New Journal of Chemistry | Year: 2011

An optimised procedure was developed for the layer-by-layer deposition of the Hofmann clathrate-like coordination compound {Fe(pyrazine)[Pt(CN) 4]} either as continuous or as nano-patterned thin films. Characterization of the thickness and topography of the thin films by atomic force microscopy (AFM) and by surface plasmon resonance (SPR) spectroscopy, which also yields the layer's refractive index and losses, are reported. We found that the films are of good optical quality and the results of both AFM and SPR experiments are in good agreement with the theoretical predictions of the films thicknesses. © 2011 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.


Sekkat Z.,Optics and Photonics Center | Sekkat Z.,Mohammed V University | Sekkat Z.,Hassan II Academy of Science and Technology | Kawata S.,Osaka University | Kawata S.,RIKEN
Laser and Photonics Reviews | Year: 2014

Recent progress in the field of single- and two-photon nanofabrication, both 2- and 3-dimensional, in photopolymerizable resins and in films of photoisomerizable azopolymers are reviewed. The basic processes as well as technological advances and applications of nanofabrication by light are discussed. Recent advances and achievements in polymer photomechanics and light-activated molecular movement in azopolymers are also reviewed. Recent progress in the field of single- and two-photon nanofabrication, both 2- and 3-dimensional, in photopolymerizable resins and in films of photoisomerizable azopolymers are reviewed. The basic processes as well as technological advances and applications of nanofabrication by light are discussed. Recent advances and achievements in polymer photomechanics and light-activated molecular movement in azopolymers are also reviewed. © 2013 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Felix G.,National Polytechnic Institute of Toulouse | Abdul-Kader K.,National Polytechnic Institute of Toulouse | Mahfoud T.,National Polytechnic Institute of Toulouse | Mahfoud T.,Optics and Photonics Center | And 6 more authors.
Journal of the American Chemical Society | Year: 2011

Nano-objects and thin films displaying molecular spin-crossover phenomena have recently attracted much attention. However, the investigation of spin crossover at reduced sizes is still a big challenge. Here we demonstrate that surface plasmon polariton waves propagating along the interface between a metal and a dielectric layer can be used to detect the spin-state changes in the latter with high sensitivity, even at the nanometer scale. © 2011 American Chemical Society.


Sekkat Z.,Mohammed V University | Sekkat Z.,Optics and Photonics Center | Sekkat Z.,Osaka University
Applied Optics | Year: 2016

Photomigration in azo polymers is an area of research that witnessed intensive studies owing to its potential in optical manipulation, e.g., optical tweezing, the physical mechanism of which remains unsolved since its discovery about two decades ago. In this paper, a detailed theoretical study that reproduces the phenomena associated with photomigration is presented, including the physical models and the associated master equations. Polarization effects are discussed and analytical solutions are given to describe the steady-state and the dynamics of photomigration. Such a theory leads to new theoretical experiments relating material properties to light action. A photoisomerization force which is described by a spring-type model is introduced. This force is derived from a harmonic light potential that moves the azo polymer. This force is parenting to optical tweezers, but it is quite different in the sense that it requires photoisomerization to occur. The azo polymer's motion is governed by four competing forces: the photoisomerization force, and the restoring optical gradient and elastic forces, as well as the random forces due to spontaneous diffusion. © 2016 Optical Society of America.


Hayashi S.,Kobe University | Hayashi S.,Optics and Photonics Center | Nesterenko D.V.,Optics and Photonics Center | Sekkat Z.,Optics and Photonics Center | And 2 more authors.
Journal of Physics D: Applied Physics | Year: 2015

We analyze in detail the plasmon-induced transparency and Fano resonance exhibited by a waveguide-coupled surface plasmon resonance sensor structure. It is shown that the results of electromagnetic calculations made for the structure agree very well with those of mechanical calculations made for two coupled harmonic oscillators. This implies that an analogy holds between the present electromagnetic system and the coupled-oscillator system. The analogy established allows us to conclude that the plasmon-induced transparency and Fano resonance are caused by the coupling between a surface plasmon polariton and a planar waveguide mode. Sensing action of the Fano resonance is also analyzed in detail. From the calculation of the figure of merit for the sensitivity by intensity, it is shown that there is an optimum condition for the coupling of the modes to achieve a maximum sensitivity. Under the optimum condition, the figure of merit is found to be three orders of magnitude higher than that of a conventional surface plasmon sensor. © 2015 IOP Publishing Ltd.


Hayashi S.,Kobe University | Hayashi S.,Optics and Photonics Center | Nesterenko D.V.,Optics and Photonics Center | Rahmouni A.,Optics and Photonics Center | And 3 more authors.
Applied Physics Letters | Year: 2016

We demonstrate experimentally the generation of narrow Fano line shapes in planar multilayer structures. The Fano line shape originates from coupling between a high loss surface plasmon polariton mode with a low loss planar waveguide mode. The line shape is shown to depend strongly on the structural parameters that govern the position of the waveguide mode and the coupling strength, and to be in good agreement with results of electromagnetic calculations. © 2016 AIP Publishing LLC.


Hayashi S.,Optics and Photonics Center | Hayashi S.,Kobe University | Nesterenko D.V.,Optics and Photonics Center | Sekkat Z.,Optics and Photonics Center | And 2 more authors.
Applied Physics Express | Year: 2015

A planar multilayer structure that allows coupling between surface plasmon polaritons and waveguide modes is proposed. Calculated reflectivity curves exhibit sharp resonances due to the Fano resonance and plasmon-induced transparency arising from the coupling. Electric field profiles obtained at the resonances demonstrate the hybrid nature of the modes excited. When the Fano resonance is used for sensing, the sensitivity with intensity modulation is enhanced by two orders of magnitude relative to that of conventional surface plasmon resonance sensors. © 2015 The Japan Society of Applied Physics


Zekriti M.,Mohammed V University | Zekriti M.,Optics and Photonics Center | Nesterenko D.V.,Optics and Photonics Center | Sekkat Z.,Mohammed V University | And 2 more authors.
Applied Optics | Year: 2015

We show, both theoretically and experimentally, that long-range surface plasmons (LRSPs) are supported by asymmetric structure, consisting of a thin silver/gold bilayer metallic film sandwiched between a magnesium fluoride (i.e., MgF2) buffer layer and a sensing medium (water). The geometrical parameters of the structure are optimized to yield efficient excitation of LRSPs by using transfer matrix method based on Fresnel reflection. The excitation of LRSPs was performed by using a custom-made automated optical setup based on angular interrogation with the precision of 0.01°. We demonstrate that the bimetallic asymmetric structure achieves better minimum reflectivity resolution than monometallic (gold) asymmetric structure. Finally, figures of merit are compared for bimetallic, monometallic, and conventional SPR structures, and we found that the bimetallic asymmetric structure provides a higher figure of merit; e.g., more than double for monometallic LRSP configuration and 8 times as compared to the conventional surface plasmon resonance sensor. © 2015 Optical Society of America.


PubMed | Osaka University and Optics and Photonics Center
Type: | Journal: Scientific reports | Year: 2016

High-Q optical Fano resonances realized in a variety of plasmonic nanostructures and metamaterials are very much promising for the development of new potent photonic devices, such as optical sensors and switches. One of the key issues in the development is to establish ways to effectively modulate the Fano resonance by external perturbations. Dynamic tuning of the Fano resonance applying the mechanical stress and electric fields has already been demonstrated. Here, we demonstrate another way of tuning, i.e., photo-tuning of the Fano resonance. We use a simple metal-dielectric multilayer structure that exhibits a sharp Fano resonance originating from coupling between a surface plasmon polariton mode and a planar waveguide mode. Using a dielectric waveguide doped with azo dye molecules that undergo photoisomerization, we succeeded in shifting the Fano resonance thorough photo-modulation of the propagation constant of the waveguide mode. The present work demonstrates the feasibility of photo-tuning of the Fano resonance and opens a new avenue towards potential applications of the Fano resonance.


PubMed | Optics and Photonics Center
Type: Journal Article | Journal: The journal of physical chemistry. B | Year: 2016

Holographic storage is one of the most important applications in the field of optics, especially for recording and retrieving data, and information storage by interference patterns in photosensitive materials are no exception in this regard. In this work, we give evidence that holograms recorded by interference of two coherent laser beams in azo dye doped polymer films can be controlled by a third incoherent assisting laser beam. We show that light diffraction can be increased or decreased by an assisting beam depending on the respective orientation of the polarizations of the recording and the assisting beams. We also found that photomanipulation of polarization holograms, prepared by polarization modulation, does not depend on the polarization of the assisting beam, whereas, photomanipulation of holograms prepared by intensity modulation strongly depends on the polarization of the assisting beam. Photoselection is shown to play a major role in the photoassisted diffraction process.

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