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Electron cyclotron motion excited surface plasmon and radiation on semiconductor thin film (Conference Presentation)
Author(s): Yung-Chiang Lan; Chia-Hui Shen

Paper Abstract

In this work, surface plasmons (SPs) on germanium (Ge) thin film that are excited by cyclotron-motion electron bunch are investigated by finite-difference time-domain simulation. The excited SPs propagate along the electron’s circular orbital. (The electron energy is 30 keV. With the magnitude of external magnetic field being 3 T, the Larmor radius and cyclotron frequency are 200 um and 4.93E11 rad/s, respectively. The optical property of Ge is described by Drude model with the high-frequency dielectric constant, plasma frequency and collision frequency to be set as 16.55, 2.1627E13 and 2.746E11, respectively. And the frequency of SPs is 3 THz.) The dispersion relations of the SPs are obtained by simulation. When adding periodic Ge gratings on the Ge thin film along the electron’s circular orbital, the SPs-manipulated Smith-Purcell radiation (SPR) will emit with the frequency of electron excited SPs. Furthermore, the emitted radiation carries optical angular momentum (OAM) due to the propagation of SPs along the circular orbital. The simulated phase distributions of emitted radiations show spiral patterns, which demonstrates they have different topological charges.

Paper Details

Date Published: 9 September 2019
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Proc. SPIE 11082, Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVII, 110820A (9 September 2019); doi: 10.1117/12.2527962
Show Author Affiliations
Yung-Chiang Lan, National Cheng Kung Univ. (Taiwan)
Chia-Hui Shen, National Cheng Kung Univ. (Taiwan)


Published in SPIE Proceedings Vol. 11082:
Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVII
Din Ping Tsai; Takuo Tanaka, Editor(s)

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