Plasmono-Atomic Quantum Metamaterial

Chan Eng Aik Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Syed Abdullah Aljunid Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Giorgio Adamo Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Martial Ducloy Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Laboratoire de Physique des Lasers, CNRS, Université Paris 13, Paris, France David Wilkowski Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Centre for Quantum Technologies, National University of Singapore, Singapore, Singapore CNRS-UNS-NUS-NTU International Joint Research Unit, Merlion MajuLab, Singapore, Singapore Nikolay Zheludev Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore Optoelectronics Reserch Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton, UK

Artistic impression of Cesium atoms interacting with the plasmonic metamaterial, resonantly excited by the laser

We report on a new type of two-dimensional material system of sub-wavelength thickness, a plasmonic metasurface in atomic gas. Such plasmono-atomic metamaterial has unique properties underpinned by the interactions in the nearfield layer of the nanostructure.

Using sub-Doppler reflective spectroscopy with tunable diode laser and hole-burning frequency reference we show that spectra of Caesium atoms are strongly affected by the Fano-like resonant coupling between atomic and plasmonic excitations. Moreover, the Caesium spectra modifications depend on the detuning between the D2 line of Caesium (6²S_1/2 – 6²P_3/2) and the dipole plasmonic absorption resonance of the nanostructure. We extract, via a precise analysis of resonant profiles, the atomic transition frequency shift induced in the nearfield of the metasurface.

Our work provide clear experimental evidence that fine structure of atomic gas lines that are only about 10MHz in width is extremely sensitive to dispersion characterising of plasmonic resonances that are typically millions times wider. We analyse possible mechanisms of such coupling, in particular those related to the Van der Waals interactions between the atoms and nanostructure.

We also report that extremely strong resonant nonlinearities can be observed in the plasma-atomic metamaterial.

Figure: Artistic impression of Cesium atoms interacting with the plasmonic metamaterial, resonantly excited by the laser.

niz@orc.soton.ac.uk