Cerenkov terahertz radiation source based on multilayer graphene surface plasma wave

Abstract

The invention discloses a Cerenkov terahertz radiation source based on a multilayer graphene surface plasma wave. The Cerenkov terahertz radiation source comprises multilayer graphene covering a substrate having a buffer layer. The multilayer graphene surface plasma wave energy can be increased by reducing the dielectric constant of the buffer layer and increasing the number of graphene layers. When the dielectric constant of the buffer layer is less than the dielectric constant of the substrate, the surface plasma wave excited by moving electrons can be directly converted into coherent Cherenkov terahertz radiation in the dielectric substrate without wave vector compensation. The radiation power density is increased by the surface plasma waves by two to three orders of magnitude. The Cerenkov terahertz radiation source can be used for developing a coherent high-power radiation source working at room temperature and covering the whole terahertz band.

Description

technical field [0001] The invention belongs to the technical field of radiation source engineering, and relates to a Cerenkov terahertz radiation source based on multilayer graphene surface plasma waves, specifically a terahertz radiation source that can be used in systems such as terahertz imaging, security inspection and communication. A source of coherent terahertz radiation. Background technique [0002] Terahertz waves lie between microwaves and infrared rays on the electromagnetic spectrum. Terahertz waves have many unique properties. First, their photon energy is low, which is lower than the bond energy of various chemical bonds, and can be used for non-destructive and safe detection of the human body and various organisms. Secondly, the wavelength of terahertz is longer than that of visible light, so it can see through smoke, etc., and has good penetration to many substances (ceramic, fat, carbon plate, cloth, plastic). Furthermore, the terahertz spectrum has a wi...

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Problems solved by technology

However, the grating structure also faces the problems of low efficiency and difficult implementation

First of all, the graphene-loaded dielectric grating structure is a periodic system. The graphene SPPs and the field in the space are the superposition of infinitely many spatial harmonics, but the SPPs only carry a small amount of energy carried by the negative first-order spatial harmonic, which is converted into Radiation field, so energy conversion is less efficient

Secondly, the surface finish of the grating whose period is only on the order of microns is very poor, and the graphene covering the surface of the grating is extremely fragile, and there are great difficulties in technical implementation

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