Attention !!! Changement d’horaire / Plasmon Assisted Si based Electo-Optical Devices

Orateur : Soutenance de Thèse de Siddharth NAMBIAR

Although the optical properties of nanostructured metals were known for many decades, it is only in the past few years that this field has attracted wide interest. This is in part due to the progress in nanofabrication techniques. The field of plasmonics is often touted as the next generation platform that could interface nanoscale electronics and Si photonics. With current electronic systems nearing saturation, the migration to photonic systems would become inevitable. Crucial to achieving this integration is to predict the electromagnetic response of these nanophotonic components. Electromagnetic numerical tools are one way to understand the optical properties of these plasmon based nanophotonic components. By and large the thesis deals with numerically analysing the propagation and near field characteristics of plasmon based components for Si photonics. The two principal EM modelling tools used in this regard are the boundary element method as well as the finite difference time domain. Two main kind of active plasmonic active devices were investigated : integrated modulators, and free space radiation photodetectors. The critical issue of an efficient coupling of light into a very confined guided plasmonic mode was first investigated so as to isolate the main modal governing contributions. Next, a new structure of plasmon assisted modulator was proposed and a complete optical design taking into the technological constraints of a CMOS foundry is provided and discussed. Finally a design optimizing the radiative coupling to the absorption of a Ge dot, using a plasmonic dipolar antenna, is studied. In particular the radiative engineering of the supporting SOI substrate is shown to have a tremendous effect on the final performance of the device.

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