Photonic crystal-based compact high-power vacuum electronic devices

V G Baryshevsky,A A Gurinovich

doi:10.1103/physrevaccelbeams.22.044702

Abstract

This paper considers how the finite dimensions of a photonic crystal placed inside a resonator or waveguide affect the law of electron beam instability. The dispersion equations describing e-beam instability in the finite photonic crystal placed inside the resonator or waveguide (a bounded photonic crystal) are obtained. Two cases are considered: the conventionally considered case, when diffraction is suppressed, and the case of direct and diffracted waves having almost equal amplitudes. The instability law is shown to be responsible for increase of increment of instability and decrease of length, at which instability develops, for the case when amplitude of diffracted wave is comparable with that of direct one, that happens in the vicinity of $\pi$-point of dispersion curve. Application of photonic crystals for development of THz sources at electron beam current densities available at modern accelerators is discussed.

Highlights

THz sources are in demand for a variety of applications: information and communications technology, biology and medicine, nondestructive investigations and homeland security, food and agricultural products quality control, global environmental monitoring, space research and ultrafast computing
The general feature for all the above listed radiation sources is the instability of an electron beam in a spatially periodic media, which results in beam self-modulation and radiation of electromagnetic waves
This paper considers how the finite dimensions of a photonic crystal placed inside a resonator or waveguide affect the law of electron beam instability

Summary

INTRODUCTION

THz sources are in demand for a variety of applications: information and communications technology, biology and medicine, nondestructive investigations and homeland security, food and agricultural products quality control, global environmental monitoring, space research and ultrafast computing. Approaches enabling increase of efficiency and transverse dimensions of interaction area (electronbeam cross section) are of high priority for THz source development Such approaches were for the first time ever proposed for x-ray range by the concept of volume free electron laser (VFEL) [9,15,16,17], which enables increase of both the efficiency and the transverse coherence area, and simultaneous reduction of threshold current density and operation length. Successive expansion of the VFEL concept to microwave [5,6,7,8,18], terahertz [19,20] and visible light [21] ranges includes both theoretical and experimental studies; diversely designed SWS are used; namely, diffraction gratings, photonic crystals, etc Another law of electron beam instability was discovered in [9,15,16,17].

Published by the American Physical Society

The current and charge densities are defined as

With growing

CONCLUSION