Selectively Enhanced Emission (SEE) near cutoff frequency in plasma and waveguide

Abstract

Powerful terahertz electromagnetic waves are a valuable source of electromagnetic radiation with significant potential in the field of science, including material diagnostics and terahertz acceleration [12]. Numerous studies have been conducted to explore terahertz generation methods, which, while powerful, often exhibit wide band spectra. Research efforts are also underway to produce monochromatic terahertz waves. In this paper, we present a novel research approach that involves driving an antenna within a cutoff region to emit powerful and monochromatic radiation. The emitted electromagnetic wave radiation disperses from the antenna into the vacuum [8,9]. Two distinct methods were employed to implement the cutoff region, which involve the use of conductive plasma and a waveguide. We achieved antenna implementation by embedding the well-known Two- color laser Terahertz method [10,11] within the cutoff region. The resulting emitted signal differs from the traditional THz signal generated through conventional means, which typically exhibits a short and broad band spectrum. Instead, the spectrum of this radiation exhibits a higher peak value at the cutoff frequency compared to conventional methods. Additionally, the shape of the THz signal resembles the theory: Selectively Enhanced Emission (SEE) [9]