Investigation of coherent molecular resonances in quantum dot-metallic nanoparticle systems using their spontaneous emission

- Investigation of collective molecular properties of quantum dot-metallic nanoparticle systems.
- Impact of such collective properties on the optical excitation of quantum dots.
- Effects of exciton-plasmon coupling in the spontaneous emission of the quantum dots.
- Signatures of plasmonic meta-resonances in the fluorescence of quantum dots.

In the presence of metallic nanoparticles the nature of the optical excitations (pumping) of semiconductor quantum dots can be determined by their molecular states and resonances formed via coherent coupling of excitons and plasmons. We show that the spontaneous emission of such quantum dots can provide key information regarding formation and characteristics of such molecular properties. This includes an ultra-fast switching process associated with optical transition between the molecular states of the quantum dot-metallic nanoparticle system or its plasmonic meta-resonance when the intensity of the laser field responsible for the exciton-plasmon coupling reaches a critical value. We also show that by varying the intensity of this laser, the spontaneous emission exhibits characteristic features indicating tunability of the molecular resonances and excitation-power dependence of plasmonic fields of the metallic nanoparticles.