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Abstract Due to their ability to strongly modify the local optical field through the excitation of surface plasmon polaritons (SPPs), plasmonic nanostructures are often used to reshape the emission direction and enhance the radiative decay rate of quantum emitters, such as semiconductor quantum dots (QDs). These features are essential for quantum information processing, nanoscale photonic circuitry, and optoelectronics. However, the modification and enhancement demonstrated thus far have typically led to drastic alterations of the local energy density of the emitters, and hence their intrinsic optical properties, leaving little room for active control. Here, dynamic tuning of the energy states of a single semiconductor QD is demonstrated by optically modifying its local dielectric environment with a nearby plasmonic structure, instead of directly coupling it to the QD. This technique leaves intact the intrinsic optical properties of the QD, while enabling a reversible all‐optical control mechanism that operates below the diffraction limit at low power levels.
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Suppressed Stokes Shifts and Hot Luminescence from Quantum Dots within Plasmonic Nanocavities
Abstract Lead sulfide (PbS) quantum dots (QDs) hold great promise for solar energy conversion, yet their efficiency is compromised by a substantial Stokes shift that adversely affects their performance in photonic devices. Here, PbS QDs are integrated within single plasmonic nanocavities, significantly mitigating Stokes shifts through Purcell enhancement of their band edge emission. This approach entails bottom‐up assembly of QDs into nanoparticle‐on‐mirror structures, leading to direct emission from band‐edge excitons with radiative lifetimes suppressed below 1 ns, a drastic decrease from the 1600 ns observed in unmodified QDs. This manipulation of the Stokes shift is attributed to the increased photonic density of states within the nanocavity, which accelerates the radiative decay process and modifies exciton relaxation pathways. These results underscore the critical role of plasmonic nanocavities in modifying QD emission characteristics, offering opportunities for enhancing QD‐based device performance across a spectrum of photonic applications.
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- Award ID(s):
- 1905217
- PAR ID:
- 10576445
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Optical Materials
- Volume:
- 13
- Issue:
- 18
- ISSN:
- 2195-1071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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