title: Wavelength-tunable spasing in the visible.
abstract: A SPASER, short for surface plasmon amplification by stimulated emission of radiation, is key to accessing coherent optical fields at the nanoscale. Nevertheless, the realization of a SPASER in the visible range still remains a great challenge because of strong dissipative losses. Here, we demonstrate that room-temperature SPASER emission can be achieved by amplifying longitudinal surface plasmon modes supported in gold nanorods as plasmon nanocavities and utilizing laser dyes to supply optical gain for compensation of plasmon losses. By choosing a particular organic dye and adjusting the doping level, the resonant wavelength of the SPASER emission can be tuned from 562 to 627 nm with a spectral line width narrowed down to 5-11 nm. This work provides a versatile route toward SPASERs at extended wavelength regimes.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University , Katsura, Nishikyo-ku 615-8510, Kyoto, Japan.
authors.forename: Xiangeng
authors.initials: X
authors.lastname: Meng
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kildishev
authors.forename: Koji
authors.initials: K
authors.lastname: Fujita
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Tanaka
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Shalaev
mesh_terms: D004735:Energy Transfer; D006046:Gold / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D055095:Optics and Photonics; D011827:Radiation; D020349:Surface Plasmon Resonance
chemical_list: D006046:Gold