Prof. Helmut Ritsch (Universität Innsbruck)
Quantum emitters forming nanoscopic polygon shaped arrays posses sub-radiant states with an exciton lifetime growing exponentially with emitter number. Placing an extra resonant dipole as absorber at the ring center creates a highly efficient single photon antenna. Interestingly for exactly nine emitters in a nonagon, as it appears in a biological light harvesting complex LHC2, we find a distinct minimum for its most dark state decay rate and a maximum of the effective absorption cross section, surpassing that for a single absorptive emitter. The dark state has dominant center occupation facilitating efficient energy absorption and fast transport. The ring concentrates incoming radiation a the centerand minimizes transport loss and time.
Prof. Helmut Ritsch (Universität Innsbruck) Dr Maria Moreno-Cardoner Mr Raphael Holzinger (Universität Innsbruck )