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Light emission from a scanning tunneling microscope is used to investigatethe electromagnetic coupling (EMC) of a metal tip and a metal sample.Subatomic scale modifications of the tip-sample region cause spectralshifts of the fluorescence as demonstrated for a monoatomic step and byvariation of the tip-sample distance. For sharp tipsthe EMC is confined to a lateral range of a few nm. The results areconsistent with model calculations of the electromagnetic response of anappropriate tip-sample geometry.
Aizpurua, J.
, Hoffman, G.
, Apell, S.
and Berndt, R.
(2002),
Electromagnetic Coupling on an Atomic Scale, Physical Review Letters
(Accessed October 27, 2025)