Étude de cristaux photoniques en silicium pour l'application à la biodétection

Abstract

This thesis is dedicated to the study and design of new structures for optical detection. Indeed, the development of these optical devices has a growing and particular interest, particularly for targeting and identifying biological species. For this purpose, the photonic crystal-based components (CPs) have been widely exploited in the field of bio-detection. Silicon is an ideal candidate designated as a support material for the realization of these devices. In this context, new coupling techniques between waveguide and optical cavity based on planar photonic crystals, made on a silicon-on-insulator (SOI) substrate, have been developed. To do this, we are modeling these bio detectors, optimizing their key parameters such as the quality factor and sensitivity to the optical index of the external environment, using commercial software Fullwave and Crystalwave that exploit the finite difference method in the two-dimensional time domain (FDTD-2D). We first studied the parallel coupling between a resonant cavity and a waveguide (W1) for application to the detection of DNA biomolecules. The originality of this study is to consider several sensors on a single platform, and to demonstrate that each sensor could detect a target independently and without interaction with others, without losses, and this, by acting on the parameters influencing the essential characteristics, we note a high sensitivity and a low limit of detection. As for the second geometry studied, it consists of another coupling path, the latter comprises two sections of guides W1 between which has been arranged a ring cavity. We have also optimized the different structural parameters for this configuration, in order to improve the sensitivity and the quality factor in order to obtain another type of high-performance sensor, namely the temperature sensor. For this, we consider the evolution of the sensitivity as a function of the change in the temperature of the water, convincing results were noted.