TY - JOUR
T1 - Disentangling cathodoluminescence spectra in nanophotonics
T2 - particle eigenmodes vs transition radiation
AU - Fiedler, Saskia
AU - Stamatopoulou, P. Elli
AU - Assadillayev, Artyom
AU - Wolff, Christian
AU - Sugimoto, Hiroshi
AU - Fujii, Minoru
AU - Mortensen, N. Asger
AU - Raza, Søren
AU - Tserkezis, Christos
N1 - Publisher Copyright:
© 2022 American Chemical Society
PY - 2022/3/23
Y1 - 2022/3/23
N2 - Cathodoluminescence spectroscopy performed in an electron microscope has proven a versatile tool for analyzing the near- and far-field optical response of plasmonic and dielectric nanostructures. Nevertheless, the transition radiation produced by electron impact is often disregarded in the interpretation of the spectra recorded from resonant nanoparticles. Here we show, experimentally and theoretically, that transition radiation can by itself generate distinct resonances that, depending on the time-of-flight of the electron beam inside the particle, can result from constructive or destructive interference in time. Superimposed on the eigenmodes of the investigated structures, these resonances can distort the recorded spectrum and lead to potentially erroneous assignment of modal characters to the spectral features. We develop an intuitive analogy that helps distinguish between the two contributions. As an example, we focus on the case of silicon nanospheres and show that our analysis facilitates the unambiguous interpretation of experimental measurements on Mie-resonant nanoparticles.
AB - Cathodoluminescence spectroscopy performed in an electron microscope has proven a versatile tool for analyzing the near- and far-field optical response of plasmonic and dielectric nanostructures. Nevertheless, the transition radiation produced by electron impact is often disregarded in the interpretation of the spectra recorded from resonant nanoparticles. Here we show, experimentally and theoretically, that transition radiation can by itself generate distinct resonances that, depending on the time-of-flight of the electron beam inside the particle, can result from constructive or destructive interference in time. Superimposed on the eigenmodes of the investigated structures, these resonances can distort the recorded spectrum and lead to potentially erroneous assignment of modal characters to the spectral features. We develop an intuitive analogy that helps distinguish between the two contributions. As an example, we focus on the case of silicon nanospheres and show that our analysis facilitates the unambiguous interpretation of experimental measurements on Mie-resonant nanoparticles.
KW - Cathodoluminescence
KW - Dielectric nanoparticles
KW - Electron-beam spectroscopy
KW - Mie resonances
KW - Mode characterization
KW - Transition radiation
U2 - 10.1021/acs.nanolett.1c04754
DO - 10.1021/acs.nanolett.1c04754
M3 - Journal article
C2 - 35286099
AN - SCOPUS:85127447937
VL - 22
SP - 2320
EP - 2327
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 6
ER -