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Unidirectional Spaser in Symmetry-Broken Plasmonic Core-Shell Nanocavity
  • Xiangeng Meng, Birck Nanotechnology Center, Purdue University; Kyoto University
  • Urcan Guler, Birck Nanotechnology Center, Purdue University
  • Alexander V. Kildishev, Birck Nanotechnology Center, Purdue University
  • Koji Fujita, Kyoto University
  • Katsuhisa Tanaka, Kyoto University
  • Vladimir M. Shalaev, Birck Nanotechnology Center, Purdue University
The spaser, a quantum amplifier of surface plasmons by stimulated emission of radiation, is recognized as a coherent light source capable of confining optical fields at subwavelength scale. The control over the directionality of spasing has not been addressed so far, especially for a single-particle spasing nanocavity where optical feedback is solely provided by a plasmon resonance. In this work we numerically examine an asymmetric spaser - a resonant system comprising a dielectric core capped by a metal semishell. The proposed spaser emits unidirectionally along the axis of the semishell; this directionality depends neither on the incident polarization nor on the incident angle of the pump. The spasing efficiency of the semishell-capped resonator is one order of magnitude higher than that in the closed core-shell counterpart. Our calculations indicate that symmetry breaking can serve as a route to create unidirectional, highly intense, single-particle, coherent light sources at subwavelength scale.

Creative Commons Attribution Licence & The final version can be found at Nature Scientific Reports's site: And the article DOI: 10.1038/srep01241

Date of this Version
Scientific Reports 3, Article number: 1241 (2013) doi:10.1038/srep01241
Citation Information
Xiangeng Meng, Urcan Guler, Alexander V. Kildishev, Koji Fujita, et al.. "Unidirectional Spaser in Symmetry-Broken Plasmonic Core-Shell Nanocavity" SCIENTIFIC REPORTS (2013)
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