Susumu Komiyama,
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| (a) Current fluctuation in matter generates black-body radiation in far field and fluctuating evanescent field in near field. (b) Electromagnetic energy densities of evanescent field uev and propagating radiation upr produced by an oscillating single electric dipole, as a function of the distance normalized by wavelength. |
https://aip.scitation.org/doi/abs/10.1063/1.5079534
A novel scanning microscope, which visualizes kinetics of charges by mapping ultrahigh frequency current fluctuation (15–30 THz), is described. This microscope, called the scanning noise microscope, scatters a fluctuating electromagnetic evanescent field on the sample surface with a sharp metal tip and detects the scattered field with an ultrahighly sensitive THz detector in a THz confocal microscope. This article describes the basic concept of the microscope, highlights the uniqueness and the general importance of the method, and demonstrates the powerfulness of the method by exemplifying experimental results made on (i) nanostructured metal layers in thermal equilibrium, (ii) narrow metal wires under non-uniform Joule heating, and (iii) operating GaAs nano-devices with non-local hot-electron energy dissipation in a highly non-equilibrium condition.
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