A customizable class of colloidal-quantum-dot spasers and plasmonic amplifiers
Abstract
Colloidal quantum dots are robust, efficient, and tunable emitters now used in lighting, displays, and lasers. Consequently, when the spaser—a laser-like source of high-intensity, narrow-band surface plasmons—was first proposed, quantum dots were specified as the ideal plasmonic gain medium for overcoming the significant intrinsic losses of plasmons. Many subsequent spasers, however, have required a single material to simultaneously provide gain and define the plasmonic cavity, a design unable to accommodate quantum dots and other colloidal nanomaterials. In addition, these and other designs have been ill suited for integration with other elements in a larger plasmonic circuit, limiting their use. We develop a more open architecture that decouples the gain medium from the cavity, leading to a versatile class of quantum dot–based spasers that allow controlled generation, extraction, and manipulation of plasmons. We first create aberration-corrected plasmonic cavities with high quality factors at desired locations on an ultrasmooth silver substrate. We then incorporate quantum dots into These cavities via electrohydrodynamic printing or drop-casting. Photoexcitation under ambient conditions generates monochromatic plasmons (0.65-nm linewidth at 630 nm, Q ~ 1000) above threshold. This signal is extracted, directed through an integrated amplifier, and focused at a nearby nanoscale tip, generating intense electromagnetic fields. More generally, our device platform can be straightforwardly deployed at different wavelengths, size scales, and geometries on large-area plasmonic chips for fundamental studies and applications. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000187079Publication status
publishedExternal links
Journal / series
Science AdvancesVolume
Pages / Article No.
Publisher
AAASOrganisational unit
03462 - Poulikakos, Dimos / Poulikakos, Dimos
03875 - Norris, David J. / Norris, David J.
Funding
339905 - Quantum-Dot Plasmonics and Spasers (EC)
146180 - Facile nanostructuring by direct printing: Fundamentals and applications in light-nanostructure interactions (SNF)
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