Free electron source design method based on threshold-free Cherenkov radiation

Abstract

The invention discloses a free electron source design method based on threshold-free Cherenkov radiation. A hyperbolic metamaterial can convert an evanescent field around electrons into a propagationfield due to its hyperbolic dispersion curve; and the speed limit of CR electrons generation is broken through in virtue of the hyperbolic metamaterial, so realization of a terahertz free electron source is made possible. Directed at the characteristics of CR generation, transmission and coupling of a low-energy electron beam in the hyperbolic metamaterial, the rules of wave vector compression andenergy flow density of CR in the hyperbolic metamaterial are explored; the method realizes the design of a terahertz free electron light source; and the terahertz free electron light source can be widely applied to the fields of biomedicine, imaging and communication.

Description

technical field [0001] The invention belongs to the technical field of high-power microwave device design, and in particular relates to a free electron source design method based on non-threshold Cerenkov radiation. Background technique [0002] When charged particles pass through a dielectric at a defined velocity threshold, the driving medium emits electromagnetic radiation called Cerenkov radiation, which was first observed in the early 20th century. The characteristic of Cerenkov radiation is that the velocity of charged particles exceeds the phase velocity of the medium. In common medium materials, the phase velocity of light is usually on the order of c*10^-1. For example, the refractive index of quartz is 2. If you want The electrons flying on the surface of the quartz produce Cherenkov radiation, and the speed of the electrons must be accelerated to 0.5C. At this time, the energy of the electrons is 100KeV, so a voltage of 100KeV must be used for acceleration. In thi...

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Problems solved by technology

The characteristic of Cherenkov radiation is that the velocity of charged particles exceeds the phase velocity of the medium. In common medium materials, the phase velocity of light is usually on the order of c*10^-1. For example, the refractive index of quartz is 2. If The electrons flying on the quartz surface produce Cerenkov radiation, and the electron speed must be accelerated to 0.5C. At this time, the electron energy is 100KeV, so a voltage of 100KeV must be used for acceleration. In this case, whether the radiation source is from It is difficult to meet the actual application conditions in terms of safety, cost or stability

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