Coherent exciton - surface plasmon polariton interactions in hybrid metal semiconductor nanostructures

We report an experimental study of the coherent coupling between Surface Plasmon Polaritons (SPPs) and Quantum Well (QW) excitons in a hybrid metal- semiconductor nanostructure, consisting of a gallium arsenide quantum well placed in a close proximity of a metal nanoslit array. Exciton-SPP coupling is probed by low-temperature angle resolved spectroscopy. Our results give evidence of a distinct modification of the exciton dispersion relation due to interaction of the exciton with SPP fields at both interfaces of the metal film. An analysis of the experimental data within a coupled oscillator model indicates coupling strengths of several tens of meV.