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New Article in Nature Comm. by Phys/Chem Collaboration

October 2, 2018 9:58 AM
“Strong coupling and induced transparency at room temperature with single quantum dots and gap plasmons.”

Physics graduate student Haixu Leng and his advisor Matthew Pelton, together with their collaborators in the UMBC Department of Chemistry & Biochemistry, have published an article in Nature Communications on coupling between plasmons and single quantum dots. Previous experiments have probed strong coupling between plasmons and individual emitters, but the signatures of strong and intermediate coupling can be confused based on the scattering measurements that have been made before. Here, the authors use both scattering and photoluminescence to unambiguously demonstrate and distinguish between weak, intermediate, and strong coupling between single quantum dots and plasmons at room temperature.

Nature Communications, Volume 9, Article number 4012 (2018)


Abstract: Coherent coupling between plasmons and transition dipole moments in emitters can lead to two distinct spectral effects: vacuum Rabi splitting at strong coupling strengths, and induced transparency (also known as Fano interference) at intermediate coupling strengths. Achieving either strong or intermediate coupling between a single emitter and a localized plasmon resonance has the potential to enable single-photon nonlinearities and other extreme light–matter interactions, at room temperature and on the nanometer scale. Both effects produce two peaks in the spectrum of scattering from the plasmon resonance, and can thus be confused if scattering measurements alone are performed. Here we report measurements of scattering and photoluminescence from individual coupled plasmon–emitter systems that consist of a single colloidal quantum dot in the gap between a gold nanoparticle and a silver film. The measurements unambiguously demonstrate weak coupling (the Purcell effect), intermediate coupling (Fano interference), and strong coupling (Rabi splitting) at room temperature.