Sujets de thèse
-
Functionnal and multimodal quantitative phase imaging in Mulhouse (68) - Université Haute-Alsace
- Le 06/03/2024
- Dans Sujets de thèse
Functionnal and multimodal quantitative phase imaging
Description: Quantitative phase imaging (QPI) becomes more and more popular in biomedical imaging, especially in optical microscopy. Unlike other methods relying on fluorescence of contrast agents, incorporated into the sample, QPI extracts phase and amplitude directly from the optical field transmitted or reflected by the object, rendering sample labeling optional. Within the IMTIS (Multimodal Imaging, Information and Signal Processing) team at IRIMAS (Institut de Recherche en Informatique, Mathématiques, Automatique et Signal), we have been developing, for about 15 years now, a generalization of QPI called Tomographic Diffractive Microscopy (TDM). By varying the object's illumination conditions, it is possible to obtain a 3D reconstruction of its complex refractive index (in absorption and refraction), with improved resolution compared to conventionnal QPI approaches.
These methods offer an interesting alternative to flurorescence microscopy, but suffer from a lack of chemical selectivity in the reconstructed information. Indeed, very different structures may have a similar refractive index. The aim of this innovative PhD proposal is to develop new approaches, in order to restore selectivity to tomographic images. Read moreWork location:
IRIMAS - IMTIS
61, rue Albert Camus
68093 MULHOUSEContacts: Nicolas Verrier (NICOLAS.VERRIER@UHA.FR), Olivier Haerberle (OLIVIER.HAEBERLE@UHA.FR)
-
Crystal photonic based SPR sensor for high sensitivity applications in Marne-la-Vallée (77) - Gustave Eiffel University
- Le 25/01/2024
- Dans Sujets de thèse
Crystal photonic based SPR sensor for high sensitivity applications
Description: Biological and chemical sensors are becoming increasingly important for environmental monitoring, medical diagnostics, and other industries such as the food industry and security. These sensors can be used to measure contaminants such as air pollutants and hazardous chemicals in air, water, or soil, and can help to provide faster, more reliable, and low-cost medical diagnostics. In addition, biosensors can be used to detect chemical contaminants in foods for ensuring safety and quality. The use of sensors in security and defence is also growing, with applications in areas such as explosives detection and bioterrorism. The photonic sensor consists of a surface in contact with the analyte, a light source, and a photodetector. The interaction of the propagating light with the surface changes its parameters or properties. Most often, it is desired to measure the variation in the refractive index related to the capture of substances surrounding the surface with the interferometry technique or by determining the spectral shift of the optical resonance. This technique allows a real-time measurement of the density of captured substances. One of the most efficient sensor categories is plasmonic sensors based on the use of the highly selective properties of surface plasmons (optical or more generally electromagnetic modes at the interface between a metal and a dielectric) which have demonstrated their superiority as chemical and biological sensors [1], [2]. These plasmonic sensors exploit the variation of light as it interacts with the surrounded medium of interest. This category of unlabelled sensors is more interesting because it does not require a preparation step to attach labels (such as fluorescent molecules) to the analytes that takes a long time to prepare, which is sometimes critical, and allows biological functions to be preserved. Another family of sensors is the one based on optical resonators where the principle is to excite a specific mode in the ring. The presence of the analyte around the resonator modifies the mode condition. The insertion of photonic crystals makes it possible to control the light, guide it and thus improve the sensitivity of the sensor. It is a form of hybridization with the aim of improving the volume of light/matter interaction [3]. Photonic crystals consist of a periodic lattice of holes or rods in the substrate. Compact sensors are needed for large scale use and deployment. Silicon photonics platform offers mature technology that could deliver innovative components integrated on a single chip. Heterogeneous III-V technology on silicon makes it possible to offer high-performance laser sources and photodetectors integration with passive components on silicon. The use of silicon photonics has many advantages such as the compactness of the compactness due to its high refractive index, low cost and its compatibility with CMOS technology. The objective of this thesis is the design of a hybrid sensor based on photonic crystals and localized surface plasmon resonance offering high-sensitivity detection. This photonic sensor operates at telecom wavelengths in order to benefit from heterogeneous III-V silicon technology. This study of this sensor topology is the first one at the Esycom laboratory, but it will benefit from the expertise of the supervisor team in modeling of metasurfaces, silicon photonics, surface plasmon devices and photonic crystals. Read more
Work location:
Gustave Eiffel University • Marne-la-Vallée Campus
5, Boulevard Descartes • Champs-sur-Marne
77454 Marne-La-Vallée CEDEX 2
FRANCEContacts:
Thesis co-directors: Catherine Algani (catherine.algani@lecnam.net), Elodie Richalot (elodie.richalot-taisne@univ-eiffel.fr)
Co-supervision: Maha BEN RHOUMA (maha.ben-rhouma@univ-eiffel.fr), Salim FACI (salim.faci@lecnam.net)