Place : USPN, Villetaneuse
Manager : Athanasios Laliotis
Context
The PhD student will participate in QUEST, an international consortium funded by the EU Marie Skłodowska-Curie Doctoral Networks program. QUEST brings together six universities and five companies from seven European countries and will train a cohort of 15 PhD students. The individual PhD projects are united by a common scientific theme, QUantum Electrodynamics with Silicon nanoTechnology, with the overarching goal of exploring and developing silicon-based quantum electrodynamics at the deep nanoscale.
This PhD project will be carried out at the Laboratoire de Physique des Lasers (LPL), Université Sorbonne Paris Nord (USPN), in the Paris area. As part of the QUEST network, possible secondments at partner institutions include Humboldt-Universität zu Berlin (K. Busch and F. Intravaia) for QED theory and modeling of Casimir–Polder forces; LENS in Florence (C. Toninelli) to explore an alternative approach to molecular cavity-QED experiments; and the Technical University of Denmark (DTU, S. Stobbe) for silicon nanocell and high-Q cavity fabrication. The student will also interact regularly with the other 14 QUEST PhD students through consortium meetings, training schools, and workshops.
The PhD student will work within the SAI team at LPL. The team has strong expertise in experimental quantum electrodynamics and nanophotonics and has developed unique spectroscopic tools to probe atomic and molecular gases at the nanoscale, with applications to Casimir–Polder interaction measurements and near-field quantum sensing. The PhD project will benefit from strong synergies within the QUEST network, as well as from the team’s extensive network of national and international collaborations. The PhD will be supervised by Assoc. Prof. Athanasios Laliotis.
Missions
Atomic gases (hot atoms) provide powerful and elegant tools for fundamental physics and for quantum sensing of electromagnetic fields. The SAI group at USPN has developed unique precision spectroscopic techniques to probe hot atomic vapors at nanometric distances from surfaces, enabling experimental tests of thermal effects in Casimir–Polder (CP) interactions, a long-elusive prediction of QED [1,2]. Extending these approaches to molecular physics is a fascinating prospect. Molecules possess a rich internal structure and ultra-narrow transitions, offering new opportunities for fundamental physics studies. The SAI group has recently extended its nanoscale spectroscopy techniques to molecular gases, pioneering precision spectroscopy in molecular thin cells [3,4].
The use of molecular rovibrational transitions opens new perspectives for photonic platforms that have traditionally relied on dielectric materials such as glass or silicon nitride. In particular, operation in the near- and mid-infrared enables the use of silicon for thin-cell (nanocell) fabrication and the development of more complex nanophotonic structures, particularly well suited for QED experiments. A major objective of this PhD project will be the fabrication of nanocells for precision measurements of molecule–surface interactions. Such interactions are of fundamental importance in physical chemistry and have attracted considerable theoretical interest because the complex geometry of molecules can give rise to anisotropic Casimir–Polder interactions. These interactions will be investigated through precision spectroscopy of acetylene or HF molecules confined in silicon nanocells. Our unique approach will directly probe differences in the surface interaction between molecular quantum states with different orientations of their rotational angular momentum relative to the surface. This platform could subsequently be extended by integrating more complex silicon nanostructures.
A further objective will be to interface acetylene, which exhibits rovibrational transitions at telecommunication wavelengths, with high-Q silicon nanocavities [5]. Coupling these two systems could provide access to molecular cavity-QED studies. Moreover, the strong confinement of electromagnetic fields within cavity gaps, on the scale of only a few nanometers, could enable molecular spectroscopy at unprecedented distances from surfaces, giving access to CP interactions in the extreme near field.
Profile
We are looking for a motivated physicist or engineer with a background in one of the following fields: quantum physics, atomic or molecular physics, photonics, laser physics, electrodynamics, or quantum optics, and with a strong interest in experimental work. Candidates must have a two-year Master’s degree (120 ECTS credits) or an equivalent degree at the same academic level. Due to the mobility rules of the Marie Skłodowska-Curie programme, candidates must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months during the 36 months immediately preceding the recruitment date.