Description du sujet de thèse

This PhD project aims to deepen our fundamental understanding of how light interacts with chiral materials placed in the near-field of photonic nanostructures. The project focuses on the identification and quantification of key physical observables such as the optical chirality density (C) and the local density of circularly polarized states (cp-LDOS). In the first part, the optical chirality density in the vicinity of nanophotonic resonators will be studied. This part will focus on measuring how chiral molecules absorb light in the vicinity of suitable nanostructures, with the aim of quantifying C. Two types of nanostructures will be studied: 1/ plasmonic gold resonators functionalized with chiral chromophores linked by DNA strands or photosynthetic proteins, 2/ silicon resonators designed to isolate contributions from electric and magnetic dipoles. The chromophore-resonator distance will be controlled by the length of the DNA strands. Varying chromophore types and resonator geometries will enable us to study the resonant interaction between photonic and electronic resonances. Polarimetric measurements of circular dichroism will be carried out using a custom-designed optical device already present in the laboratory. In the second part, we will explore how the local chiral electromagnetic environment affects light emission from single emitters, targeting the measurement of cp-LDOS. DNA origami techniques will be used to position chromophores with nanometer precision in the vicinity of gold nano-sticks used as photonic resonators. The polarized photoluminescence of a single particle will be measured using a polarimeter integrated into a microscope. This experimental thesis will be complemented by numerical modelling (commercial software).

Contexte de travail

The Institut des NanoSciences de Paris (INSP) is a 182-strong joint research unit located on Sorbonne University's Pierre et Marie Curie campus. The PhD will be carried out in the 'Nanophotonics and Quantum Optics' team at the INSP. The work will be co-directed by M. Sanz-Paz and B. Gallas, both CNRS researchers. The candidate will be a physicist with a solid background in materials science, although knowledge of plasmonics and initial experience in grafting molecules onto resonators will be appreciated. The candidate will have a keen interest in experimental physics. Although the work will be carried out at INSP, the PhD will take place in a collaborative environment.
The project is financed within the framework of PEPR, which implies validation of the candidates by the Defence Security Officer.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Laser