Étude des composants à base de cristaux photoniques

Abstract

Nowadays, the development of biological sensors has become a major issue in order to meet the current and the future needs in diverse areas demanded. Real-time detection or analysis should be preferred and the response should be easy to read and extremely fast. In parallel, the progress of nanotechnologies and in particular those of photonic crystals, which make it possible to manipulate the light at nanometric resolution, and thus at the biomolecule scale, offers the possibility of achieving a new high-performed detection platform. In this context, this thesis aims to study and to design refractive index biosensors based on photonic crystals. The structures proposed are essentially based on a H0 cavity coupled waveguide system. The main objective of our work remains the enhancement of light confinement within the cavity area. In the first part of this work we analyze in detail the influence of the cavity geometry on the detection performances. Thus, we present a configuration based on ringed air holes to improve the detection properties. In order to integrate several detection units in the same photonic crystal platform, the wavelength division demultiplexing (WDM) technique to spatially separate the responses of the integrated biosensors will be studied: Two structures of demultiplexers based on a selective filtering will also be presented. As for the case of a single biosensor and based on this technique the configurations of classical and ringed biosensor array will be studied and simultaneously evaluated. The optical properties of these photonic structures will be numerically evaluated by performing simulations based on the finite difference time domain (FDTD) method. The obtained results indicate that the response of each sensor unit shifts independently in terms of refractive index variations. Accordingly, a sensitivity of 450 nm / RIU and a crosstalk of less than -43.78 dB have been achieved for the ringed configuration, while maintaining a quality factor as high as 5.74×104. These features make the designed structure a promising platform for performing monolithic integration and high multiplexed label-free detection.