Renaud Vallee1 Brahim Lounis2 Daniel Neuhauser3 Maxim Sukharev4

1, Centre de Recherche Paul Pascal (CNRS, UPR8641), Pessac, , France
2, Laboratoire Photonique Numérique et Nanosciences, Talence, , France
3, University of California, Los Angeles, Los Angeles, California, United States
4, Arizona State University, Phoenix, Arizona, United States

Hybridisation of quantum emitters and plasmonic nano-structures has attracted much attention over the last years, due to their interest in the design of plasmon-based nano-lasers [1,2] or to achieve long-range qubit entanglement [3,4]. Recent theoretical studies [5,6] suggest a plasmonic super-radiant mechanism to increase the rate of emitters, similar to Dicke super-radiance [7].
In this talk, we will report a review of our work in these domains and explain the salient features of the involved effects.
As such, i) we provide experimental evidence of plasmonic super-radiance of organic emitters close to a metal nanosphere at room temperature. This observation of plasmonic super-radiance at room temperature opens questions about the robustness of these collective states against decoherence mechanisms which are of major interest for potential applications.
Ii) We propose a new type of nanodevice, capable of both path-selectivity and anisotropic lasing that is based on loss-compensation and amplification by a localized plasmon polariton [8]. The nano-device is a Y-shaped plasmonic nanostructure embedded in an anisotropic host medium with gain. The anisotropy leads to the path selectivity, an effect which is more pronounced once gain is included. The path-selectivity may be coupled with activation of a rotation of the anisotropic host medium for inducing a light-guiding switching functionality.
Finally, iii) we demonstrate both experimentally and theoretically how to manipulate strong coupling between the Bragg-plasmon mode supported by an organo-metallic array and molecular excitons in the form of J-aggregates dispersed on the hybrid structure [9]. We observe experimentally the transition from a conventional strong coupling regime exhibiting the usual upper and lower polaritonic branches to a more complex regime, where a third nondispersive mode is seen, as the concentration of J-aggregates is increased. The numerical simulations confirm the presence of the third resonance. We attribute its physical nature to collective molecule-molecule interactions leading to a collective electromagnetic response. It is shown that at the energy of the collective mode molecules oscillate completely out of phase with the incident radiation acting as an effective thin metal layer.
[1] J.G. Bohnet et al. Nature 484, 78–81 (2012).
[2] M.A. Noginov et al., Nature 460, 1110–2 (2009).
[3] R. Kolesov et al., Nature Physics 5, 470–474 (2009).
[4] A. Gonzalez-Tudela et al., Phys. Rev. Lett.106, 020501 (2011).
[5] V.N. Pustovitet al., Phys. Rev. Lett.102, 077401 (2009).
[6] D. Martín-Cano et al., Nano Letters 10, 3129–3134(2010).
[7] R.H. Dicke. Phys. Rev.93, 99-110 (1954).
[8] A. Yamada, D. Neuhauser and R. A. L. Vallée. Nanoscale 8, 18476–18482 (2016).
[9] P. Fauché, C. Gebhardt, M. Sukharev, M., R. A. L. Vallée (2017). Scientific Reports 7, 4107 (2017).