Étude Théorique D’un Capteur À Base D’une Structure Originale En Cristaux Photoniques.

Résumé: In this thesis we consider the study and the design of new structures of refractive index sensors based on two-dimensional photonic crystals, and in particular their exploitation in detection domain. The proposed structures are focalized particularly for detecting the refractive index variation. They consist of a guide / cavity coupling according to two configurations. The first configuration consists of a linear coupling (filter). The second configuration is based on a lateral coupling which consists of a juxtaposed linear cavity parallel to the waveguide. Another original structure proposed consists of an air-slot width-modulated line-defect microcavity. Simulations are performed using the BandSOLVE and FullWAVE simulation software developed by RSoft, based on the Plane Wave Method (PWE) and the Finite Difference Time Domain method (FDTD), respectively. Firstly, we are optimized the quality factor and the transmission, modifying the physical and geometric key parameters of the structure such as: size, position and shape of holes. We studied the sensitivity by optimizing the detection performance (sensitivity and detection limit). To do this, we introduced an air slot in the cavity center. This configuration makes it possible to considerably increase the light-matter interaction and induces a strong confinement of the light within the cavity. Obtained results concerning the sensitivity are convincing: S = 400 nm / RIU: this structure can be used as an index variation sensor.

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