Cerenkov radiation source of surface plasma waves

Abstract

A Cerenkov radiation source of surface plasma waves belongs to the technical field of electromagnetic wave radiation sources, and comprises an electron gun, a medium material layer and a metallic film layer deposited on the surface of the medium material layer. Electron beams emitted by the electron gun skim over the surface of the metallic film layer to excite surface plasma waves on the surface of the metallic film layer, and the surface plasma waves penetrate the metallic film layer to reach the medium material layer; when the ratio Beta between the movement speed of the electron beams emitted by the electron gun and the light velocity in vacuum, and the refractive index n of the medium material layer satisfy the Cerenkov radiation condition that n Beta is larger than 1, the surface plasma waves are converted into Cerenkov radiation in the medium material layer; the radiation frequency is determined by the frequency of the surface plasma waves; and through changing the energy of moving electrons, the frequency of the excited surface plasma waves can be changed, so that the frequency of the electromagnetic radiation source can be tuned. The Cerenkov radiation source has the characteristics of miniaturization, narrow bandwidth, tunability, low voltage and easiness in integration.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic radiation sources, and relates to a novel tunable electromagnetic radiation source that combines electronics and photonics, converts surface plasma waves into Cerenkov radiation, and works from visible light to ultraviolet light. Background technique [0002] Theoretical and experimental studies have shown that moving electrons can excite surface plasmon waves on the metal surface, especially when the metal thickness is relatively thin (less than the skin depth δ in the metal m ), surface plasmon waves exist on both sides of the thin metal layer. Since the surface plasmon wave is a surface wave, its field decays exponentially along the direction perpendicular to the metal surface. To use surface plasmon waves as radiation sources, the key problem to be solved is how to convert surface plasmon waves into radiation fields. [0003] Due to the high frequency (from visible light to ultraviol...

AI Technical Summary

Problems solved by technology

Although the free electron laser has the advantages of tunability, high efficiency, and high power, it also has the disadvantages of large volume, complex structure, high working voltage, and the need for periodic swinging magnetic fields.

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