Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 18: Plasmons, plasmonic laser, and spaser

HL 18.4: Talk

Monday, March 16, 2015, 16:30–16:45, EW 203

Theoretical studies on a plasmonic nano-laser: plasmon excitation and emission line narrowing due to the presenec of many molecules — •Yuan Zhang and Volkhard May — Institut für Physik, Humboldt Universität zu Berlin, Netonstrasße 15, D-12489 Berlin, Germany

Strong plasmon excitation and photon emission is demonstrated for a plasmonic nano-laser (SPASER) consisting of a gold nano-sphere coated by many dye molecules. An exact description of this system in the framework of density matrix theory becomes possible if all molecules are treated as identical units. Due to their external and simultaneous excitation the molecules overcome the huge plasmon damping. By increasing the number of molecules, the photon emission intensity increases and the emission line-shape becomes narrowed. Thus, such results can be related to plasmonic lasing. Beside optical pumping of the molecules also a mechanism of electrical pumping is considered. It is realized via electron transfer between the molecules and two leads forming a molecular junction. The exact quantum-dynamics simulations are extended up to 20 molecules covering the nano-sphere.