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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. Source


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. Source


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. Source


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. Source


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 Source

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