TY - JOUR
T1 - Nanoscale imaging of light-matter coupling inside metal-coated cavities with a pulsed electron beam
AU - Moerland, Robert Jan
AU - Weppelman, Gerward
AU - Scotuzzi, Marijke
AU - Hoogenboom, Jacob P.
PY - 2018
Y1 - 2018
N2 - 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.
AB - 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.
KW - cathodoluminescence
KW - decay dynamics
KW - electron microscopy
KW - local density of states
KW - nanocavities
UR - http://resolver.tudelft.nl/uuid:05a1f26d-6373-4d9e-84b0-f9605c712c30
UR - http://www.scopus.com/inward/record.url?scp=85046531289&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.8b00546
DO - 10.1021/acs.nanolett.8b00546
M3 - Article
AN - SCOPUS:85046531289
SN - 1530-6984
JO - Nano Letters: a journal dedicated to nanoscience and nanotechnology
JF - Nano Letters: a journal dedicated to nanoscience and nanotechnology
ER -