Integration sur silicium de capteurs plasmoniques a base de nanostructures periodiques.

摘要

Surface plasmon resonance was first observed at the beginning of the 20th century, and since then, it has been extensively studied, both theoretically and experimentally. Surface plasmons originate from a collective excitation of electrons in a metal, electrons behaving as a single particle. This resonance is highly sensitive to optical properties of involved dielectric mediums, thus making it a useful tool in fields related to biosensing and pharmaceutical research. Surface plasmons require specific excitations conditions, and since the 90s and the theoretical explanation of extraordinary light transmission through array of nanoholes in a thin metallic film by plasmon excitation, a new interest for these structures has arisen for biosensing applications. In this master thesis, we propose different ideas and systems to better exploit these nanostructures in order to build high resolution integrated biosensors.;These nanostructures also offer a simple way to excite surface plasmon, transmitted light being collected by a simple detector directly after the array. This led us to think of ways to integrate those structures directly on an active semiconductor substrate, and exploiting its optoelectronic properties. Thin metallic film has two roles, transducer for sensing purpose, and electrode for photodetection in the semiconductor. Modulation of the incident light polarization allows for a balanced detection, thus increasing the resolution of the overall integrated sensor, giving a value of 3.5 x 10-5 RIU.;his study shows an example of a miniaturized sensor based on plasmonic nanostructures, directly integrated on an active semiconductor substrate, thus offering new and promising applications in high resolution fast-response hand-help devices based on surface plasmon resonance. Different ideas based on a semiconductor-based integration of sensor are also proposed, for possible use in imaging devices and biosensing.;Polarization dependence of surface plasmon resonance led us to design and test arrays of nanoholes in a gold film, having different periods along the polarization directions. Transmission peaks are then controlled by those different periods in the arrays. Circular nanoholes arrays, of diameter 200nm and respective periods of 380 and 420nm, have been fabricated and tested. Experimental set up based on a balanced detection scheme allows simultaneous detection of signals from two perpendicular polarizations, thus noise can be reduced by comparing the signals. System resolution has been measured to be 6.4 x 10-6 RIU, thus gaining an order of magnitude compared to existing publications.