Title of research project

PhD position in Precision Casimir-Polder and cavity QED experiments

PhD position, MSCA-DN funding

Contract type Contrat (CDD) Category Workload Fulltime

Scientific field Physique

WorklJob Descriptionoad

Description of the offer 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. Objectives/tasks 1. Fabrication of nanocells filled with molecular gases (acetylene or HF). 2. Spectroscopic probing of molecular gases confined within 100 nm gaps, and precision measurements of the Casimir-Polder interaction. 3. Theoretical modeling of Casimir-Polder, molecule-surface interactions. 4. Coupling of acetylene gases with high-Q silicon nanocavities. References 1. A. Laliotis, T. P. de Silans, I. Maurin, M. Ducloy, and D. Bloch, “Casimir–Polder interactions in the presence of thermally excited surface modes,” Nat. Commun. 5, 4364 (2014). 2. J. C. de Aquino Carvalho, I. Maurin, P. Chaves de Souza Segundo, A. Laliotis, et al., “Revealing Some Disagreements between a Casimir-Polder Sensor and Predictions from Far-Field Emittance,” Phys. Rev. Lett. 131, 143801 (2023). 3. J. Lukusa Mudiayi, I. Maurin, T. Mashimo, J. C. de Aquino Carvalho, D. Bloch, S. K. Tokunaga, B. Darquié, and A. Laliotis, “Linear Probing of Molecules at Micrometric Distances from a Surface with Sub-Doppler Frequency Resolution,” Phys. Rev. Lett. 127, 043201 (2021). 4. G. G. Arellano, J. C. de Aquino Carvalho, H. Mouhanna, E. Butery, T. Billeton, F. Du-Burck, B. Darquié, I. Maurin, and A. Laliotis, “Probing molecules in gas cells of subwavelength thickness,” Nat. Commun. 15, 1862 (2024). 5. A. N. Babar, T. A. S. Weis, K. Tsoukalas, S. Kadkhodazadeh, G. Arregui, B. Vosoughi Lahijani, and S. Stobbe, “Self-assembled photonic cavities with atomic-scale confinement,” Nature 624, 57–62 (2023).

Field of research Quantum Physics

Skills Aptitude for experimental work, Autonomy, Rigor, Academic excellence

Knowledge Quantum physics, atomic and molecular physics, photonics

Work environment

Location Villetaneuse

Laboratory Laboratoire de Physique des Lasers

Degree level

Degree required Masters degree

Experience required 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.

Additionnal information

Start date 04 01 27

Job Type Contrat (CDD)

Salary 3305 € per month

Contract duration 3 ans

Composition of the selection jury

Application deadline 02 01 27

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