Thèse de doctorat en Electronique, Electrotechnique et Automatique
Soutenue le 22-11-2012
à l'Ecully, Ecole centrale de Lyon , dans le cadre de École doctorale Électronique, électrotechnique, automatique (Lyon) .
Le président du jury était Natalia Del Fatti.
Nanodispositif hybride plasmonique-photonique
Pas de résumé
Metallic nano-particles or nano-antennas (NAs) provide a strong spatial confinement down to the sub wavelength regime. However, a key challenge is to address and collect light from those nano-scale systems. The tiny active area of the NA is both an advantage for its miniaturization, and a real limit for the level of the collected signal. Therefore, one needs to reconsider how to drive efficiently such NA. Here, we propose to tackle this important issue by designing and realizing a novel nano-optical device based on the use of a photonic crystal cavity (PC cavity) to generate an efficient coupling between the external source and a NA. In this thesis, we design and realize a novel nano-optical device based on the coupling engineering of a photonic crystal (PC) cavity and a nanoantenna (NA). The research work includes nanodevice design, fabrication and characterization. The PC structures are formed in an InP-based membrane with four InAsP quantum wells are in the centre of the membrane to act as an optical gain material of laser mode. The PC structures include defect mode PC structures and Bloch mode PC structures. The bowtie NAs are placed on the backbone of the PC structures. The fabrication of the PC is done by electron beam lithography. Reactive ion beam etching (RIBE) is used to transmit the patterns of PC structures into the InP layer. The NAs are then deterministically positioned on the PC structures by a second e-beam exposure followed by a lift-off process. Overlay measurements showed that the deviation in the alignment error could be as small as 20nm.Optical properties of the hybrid structure are investigated in both far-field and near-field. The far-field measurement shows that the NA increases the lasing threshold of the PC cavity. The wavelength of the laser is also impacted. Near-field scanning optical microscopy (SNOM) has employed to investigate the near-field optical field distribution. The measurement results show that the NA modifies the mode of the structure and localizes the optical field under it. The modification depends on the position and orientation of the NA.