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Ultrafast spontaneous emission source using plasmonic nanoantennas.

Hoang TB, Akselrod GM, Argyropoulos C, Huang J, Smith DR, Mikkelsen MH - Nat Commun (2015)

Bottom Line: The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter.We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%.The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, Duke University, Durham, North Carolina 27708, USA. [2] Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708, USA.

ABSTRACT
Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1-10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sources and lasers. Here we experimentally demonstrate an ultrafast (<11 ps) yet efficient source of spontaneous emission, corresponding to an emission rate exceeding 90 GHz, using a hybrid structure of single plasmonic nanopatch antennas coupled to colloidal quantum dots. The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter. We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%. The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

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Increased spontaneous emission rate of QDs coupled to NPAs.(a) Normalized time-resolved fluorescence of QDs on a glass slide (red) compared with QDs on a Au film (blue) and coupled to a single NPA (green). The instrument response function (IRF) is also shown33. Fits to exponential functions convolved with the IRF are shown in black. A single exponential function is used for the QDs on glass and Au. A biexponential function is used to fit the NPA decay. (b) Scatter plot of fluorescence decay times for ∼30 NPAs showing the relative intensity contributions of the fast and slow decay components. The dashed line connects the two components for each individual NPA. Some decay curves show a more robust fit to a single exponential, and, in these cases, the slow component is not shown. (c) A histogram showing the decay time distribution of the fast and slow components of the ∼30 individually measured NPAs.
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f4: Increased spontaneous emission rate of QDs coupled to NPAs.(a) Normalized time-resolved fluorescence of QDs on a glass slide (red) compared with QDs on a Au film (blue) and coupled to a single NPA (green). The instrument response function (IRF) is also shown33. Fits to exponential functions convolved with the IRF are shown in black. A single exponential function is used for the QDs on glass and Au. A biexponential function is used to fit the NPA decay. (b) Scatter plot of fluorescence decay times for ∼30 NPAs showing the relative intensity contributions of the fast and slow decay components. The dashed line connects the two components for each individual NPA. Some decay curves show a more robust fit to a single exponential, and, in these cases, the slow component is not shown. (c) A histogram showing the decay time distribution of the fast and slow components of the ∼30 individually measured NPAs.

Mentions: Having established the high QE of QDs coupled to single NPAs, we turn to time-resolved fluorescence measurements to demonstrate the enhancement of the spontaneous emission rate. Figure 4a shows the normalized time dependence of the emission of QDs on glass, on a Au film, and coupled to a single NPA. The decay of QDs on a glass slide features a single exponential component with a lifetime of τglass=9.7±0.1 ns. On a Au film without nanocubes, the QDs show a shortened lifetime of τgold=0.8±0.03 ns but with a significantly reduced intensity, as shown in Fig. 3a, which is the result of direct metal quenching2442.


Ultrafast spontaneous emission source using plasmonic nanoantennas.

Hoang TB, Akselrod GM, Argyropoulos C, Huang J, Smith DR, Mikkelsen MH - Nat Commun (2015)

Increased spontaneous emission rate of QDs coupled to NPAs.(a) Normalized time-resolved fluorescence of QDs on a glass slide (red) compared with QDs on a Au film (blue) and coupled to a single NPA (green). The instrument response function (IRF) is also shown33. Fits to exponential functions convolved with the IRF are shown in black. A single exponential function is used for the QDs on glass and Au. A biexponential function is used to fit the NPA decay. (b) Scatter plot of fluorescence decay times for ∼30 NPAs showing the relative intensity contributions of the fast and slow decay components. The dashed line connects the two components for each individual NPA. Some decay curves show a more robust fit to a single exponential, and, in these cases, the slow component is not shown. (c) A histogram showing the decay time distribution of the fast and slow components of the ∼30 individually measured NPAs.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4525280&req=5

f4: Increased spontaneous emission rate of QDs coupled to NPAs.(a) Normalized time-resolved fluorescence of QDs on a glass slide (red) compared with QDs on a Au film (blue) and coupled to a single NPA (green). The instrument response function (IRF) is also shown33. Fits to exponential functions convolved with the IRF are shown in black. A single exponential function is used for the QDs on glass and Au. A biexponential function is used to fit the NPA decay. (b) Scatter plot of fluorescence decay times for ∼30 NPAs showing the relative intensity contributions of the fast and slow decay components. The dashed line connects the two components for each individual NPA. Some decay curves show a more robust fit to a single exponential, and, in these cases, the slow component is not shown. (c) A histogram showing the decay time distribution of the fast and slow components of the ∼30 individually measured NPAs.
Mentions: Having established the high QE of QDs coupled to single NPAs, we turn to time-resolved fluorescence measurements to demonstrate the enhancement of the spontaneous emission rate. Figure 4a shows the normalized time dependence of the emission of QDs on glass, on a Au film, and coupled to a single NPA. The decay of QDs on a glass slide features a single exponential component with a lifetime of τglass=9.7±0.1 ns. On a Au film without nanocubes, the QDs show a shortened lifetime of τgold=0.8±0.03 ns but with a significantly reduced intensity, as shown in Fig. 3a, which is the result of direct metal quenching2442.

Bottom Line: The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter.We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%.The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, Duke University, Durham, North Carolina 27708, USA. [2] Center for Metamaterials and Integrated Plasmonics, Duke University, Durham, North Carolina 27708, USA.

ABSTRACT
Typical emitters such as molecules, quantum dots and semiconductor quantum wells have slow spontaneous emission with lifetimes of 1-10 ns, creating a mismatch with high-speed nanoscale optoelectronic devices such as light-emitting diodes, single-photon sources and lasers. Here we experimentally demonstrate an ultrafast (<11 ps) yet efficient source of spontaneous emission, corresponding to an emission rate exceeding 90 GHz, using a hybrid structure of single plasmonic nanopatch antennas coupled to colloidal quantum dots. The antennas consist of silver nanocubes coupled to a gold film separated by a thin polymer spacer layer and colloidal core-shell quantum dots, a stable and technologically relevant emitter. We show an increase in the spontaneous emission rate of a factor of 880 and simultaneously a 2,300-fold enhancement in the total fluorescence intensity, which indicates a high radiative quantum efficiency of ∼50%. The nanopatch antenna geometry can be tuned from the visible to the near infrared, providing a promising approach for nanophotonics based on ultrafast spontaneous emission.

No MeSH data available.


Related in: MedlinePlus