Thesis defense of Sandrine VILLENAVE

Thesis defense of Sandrine VILLENAVE, PhD student in the Nanophotonics group of the LCF, on Thursday 14 December 2023 at the Maison Minatec, salle Palladium 2 in Grenoble, on the topic: "Development and integration of CMOS technology structures for multispectral filtering."

Abstract: "Optical sensors are increasingly present in fields such as health, environment, and food. Spectrometers hold a special place, allowing the qualification and quantification of many chemical species. A spectrometer integrated onto a CMOS sensor in an extremely portable solution would then be an analysis tool accessible to everyone, via the smartphone which is a highly advanced object widely spread throughout the world. To create such a spectrometer, we studied guided mode resonance filters (RWGs), focusing on the parameters useful to design filters for multispectral applications, while keeping in mind the requirement to integrate them on CMOS sensors. We then detailed the design of these filters through simulation (RCWA/FMM), their fabrication on the 300 mm platform of ST Crolles (CMOS foundry), and we showed and analyzed encouraging experimental results, measured at CEA Leti. Then we looked at the drawbacks of RWGs, and we proposed structures close to RWGs that overcome some of these drawbacks while maintaining the functionality of tunability via the planar geometry of a grating. Finally, we made a first application of these filters, in two distinguished steps. These encouraging results open the door to developments and improvements, either on filtering structures or on more advanced postprocessing of signals such as those filtered by existing structures."