Experimental Verification of the Theory on Energy Modulation of an Electron Beam with an Optical Near-Field

Ryo ISHIKAWA  Jongsuck BAE  Koji MIZUNO  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.12   pp.2086-2092
Publication Date: 2002/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Near-Field Optics and Its Applications)
optical near field,  evanescent wave,  free electron,  microslit,  electron energy modulation,  

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An exchange of energy between nonrelativistic electrons and evanescent waves in an optical near-filed has been investigated in an infrared region. A metal microslit has been adopted as an optical near-field generator which produces a number of evanescent waves by illumination of a laser beam. The theory has predicted that electrons interact selectively with the evanescent wave whose phase velocity is equal to the velocity of the electrons. In order to verify the theory, two types of precise microslits with different shapes, a slot and a V-shaped groove, have been fabricated. Experiments performed using these slits at the wavelength of 10.6 µm have shown that the energy change of the electrons has varied from 2 eV to 13 eV with their initial energy between 25-95 keV for a 3.2 kW CO2 laser pulse. The measured results have given experimental verifications to the theory.