The PhD defense of Matthieu Baillergeau, realized under the supervision of Juliette Mangeney and Takis Kontos, will take place on December 10 at 2:30pm in salle Dussane at Ecole Normale Supérieure, 45 rue d’Ulm, 75005 Paris.
In the last ten years, research has been devoted to the development of hybrid architecture mesoscopic circuit to study the light-matter interaction in the microwaves range. These improvements allow us to study this interaction in the terahertz range extending from 0.1 THz to 10 THz (0.4 meV - 41.3 meV). Moreover, new efficient sources and new spectroscopy schemes like time domain spectroscopy set-up are some tools that can be used to study the light-matter interaction in this range.
In this work, we developed a paradigm to study the interaction composed of a carbon nanotube in a quantum dot regime embedded in a terahertz cavity. Carbon nanotube quantum dot is well adapted because of its electronic levels which are separated by energy in the terahertz range. The cavity used for the study is a "split ring resonator". This thesis is decomposed in two parts. Firstly, we built an ultrabroadband terahertz time domain spectroscopy set-up (0.3 THz -20 THz) to study the terahertz resonators. We demonstrated that the terahertz field is focused at the diffraction limit by exciting the antenna with an original scheme based on a control wavefront of the emitted terahertz
field. Then, electronic transport measurements have been done to highlight the coupling between the cavity and the quantum dot. A coupling with a bosonic mode is observed. The conductance of these states is modified by the source that we used in this work. These first observations are some clues that highlight the coupling between the terahertz photons and the electronic level of the quantum dot. These works open perspectives for the study of mechanisms in the terahertz range in this kind of system.