Modélisation des structures planaires chiroptiques

Abstract

The chiral media have a major interest in scientific research. Their characteristics have given rise to new amazing applications. In our research we studied the effects of chirality in transmission; and the specific properties thereto, such as its optical rotation, the circular dichroism and nonlinear effects. Our work was divided into four parts: In the first part, we have calculated and made a comparative study between different formalisms used to define the influences of biisotropes environments, and the chiral environments on the characteristics of the modal dispersion. Matlab program was developed to confirm these characteristics. The second part relates to a new mathematical approach, which was proposed for the value of the nonlinear effect setting in a chiral environment, due to its magnetization under the effect of a strong electric field. However chiral media have a coupling between electric and magnetic quantities. This results in the constitutive equations in that the polarization and magnetization vectors depend on both the electric and magnetic fields. A theoretical study of a light pulse propagating in a chiroptical fiber considering with Kerr effect is presented in the third part. The novel effects of chirality are characterized through our proposed formalism, to highlight the nonlinear effect in a chiral medium, which is due to the magnetization vector under the influence of a strong electric field. These simulations are based on the Split-Step Fourier method for solving the nonlinear Schrödinger equation. The latter is one of the most used pseudo-spectral methods to study the propagation of pulses in media, nonlinear and dispersive. The obtained results presented in this paper illustrate nonlinear chirality parameter that becomes the key factor to estimate chiroptical fiber dispersion and nonlinearity. In the fourth part, our practical work carried out in the laboratory of Research at the Institute of Light and Matter, Lyon 1 University, focuses on the characterization of the structures chiroptical with ellipsometry spectroscopy to measure the coupling term TM/TE reflection on a chiral surface. We propose a new assembly based on the calculation according to the Stokes-Mueller formalism, where we showed how to determine the chirality elements for the various possible configurations of this assembly.