Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 29: Quantum Effects

Q 29.7: Talk

Wednesday, March 13, 2019, 12:15–12:30, S Gr. HS Maschb.

Collective dipole-dipole interactions in planar cavities — •Helge Dobbertin and Stefan Scheel — Institut für Physik, Uni- versität Rostock, Albert-Einstein-Straße 23, 18059 Rostock, Germany

When densely spaced atoms are subject to near-resonant light, they couple via strong dipole-dipole interactions and react collectively. Recent experiments [1] observed the collective response of a thermal atomic vapour confined in a nano-cell. Here we calculate the corresponding transmission spectra from first principles by means of a microscopic coupled-dipole model at intermediate atomic densities. We incorporate the influence of the cavity environment on single-atom properties (Casimir–Polder and Purcell effects) and on atom-atom interactions. Our model shows the emergence of a macroscopic effective medium theory with refractive index n from the microscopic level. Furthermore, we study the resulting line broadening and line shift including a geometry-dependent shift, called ’collective Lamb shift’, which we show to be an entirely classical effect [2]. Our approach may be used to identify and study new vapour-cell based structures with collectively enhanced light-matter interaction.

[1] T. Peyrot et al., Phys. Rev. Lett. 120, 243401 (2018).

[2] J. Javanainen et al., Phys. Rev. A 96, 033835 (2017).