Electromagnetic Wave Emission by a Quasi-One-Dimensional Ballistic Ring in a Uniform Electric Field

Abstract

Dipole emission of electromagnetic waves by an electron in a ballistic quasi-one-dimensional ring is investigated. The ring is placed in a uniform constant electric field F, parallel to the ring plane. With increasing field in the range 0 < F < E/2eR (E - electron energy, R - radius of the ring) the frequency of radiation decreases, and higher harmonics appear so that thickening of the discrete spectrum occurs. At F = E/2eR the electron moves aperiodically and the radiation spectrum is continuous. With further increasing field thinning of the spectrum occurs, and the intensity of the higher harmonics falls. At F → ∞ the radiation becomes monochromatic with frequency that rises as √F. The steady component of the dipole moment vanishes at F ≈ E / 1.66eR and crossover takes place between paraelectric and diaelectric behaviors.