Nanoscale imaging of light-matter coupling inside metal-coated cavities with a pulsed electron beam

Nanoscale imaging of light-matter coupling inside metal-coated cavities with a pulsed electron beam

Moerland, R.J. (TU Delft ImPhys/Quantitative Imaging)
Weppelman, I.G.C. (TU Delft ImPhys/Charged Particle Optics)
Scotuzzi, M. (TU Delft ImPhys/Charged Particle Optics)
Hoogenboom, J.P. (TU Delft ImPhys/Charged Particle Optics)

2018

Many applications in (quantum) nanophotonics rely on controlling light-matter interaction through strong, nanoscale modification of the local density of states (LDOS). All-optical techniques probing emission dynamics in active media are commonly used to measure the LDOS and benchmark experimental performance against theoretical predictions. However, metal coatings needed to obtain strong LDOS modifications in, for instance, nanocavities, are incompatible with all-optical characterization. So far, no reliable method exists to validate theoretical predictions. Here, we use sub-nanosecond pulses of focused electrons to penetrate the metal and excite a buried active medium at precisely-defined locations inside sub-wavelength resonant nanocavities. We reveal the spatial layout of the spontaneous-emission decay dynamics inside the cavities with deep-subwavelength detail, directly mapping the LDOS. We show that emission enhancement converts to inhibition despite an increased number of modes, emphasizing the critical role of optimal emitter location. Our approach yields fundamental insight in dynamics at deep-subwavelength scales for a wide range of nano-optical systems.

cathodoluminescence
decay dynamics
electron microscopy
local density of states
nanocavities

http://resolver.tudelft.nl/uuid:05a1f26d-6373-4d9e-84b0-f9605c712c30

https://doi.org/10.1021/acs.nanolett.8b00546

1530-6984

Nano Letters: a journal dedicated to nanoscience and nanotechnology

Institutional Repository

journal article

© 2018 R.J. Moerland, I.G.C. Weppelman, M. Scotuzzi, J.P. Hoogenboom