A quantum mechanical analysis of Smith–Purcell free-electron lasers
نویسندگان
چکیده
The paper presents a quantum mechanical treatment for analyzing the Smith–Purcell radiation generated by charged particles passing over a periodic conducting structure. In our theoretical model, the electrons interact with a surface harmonic wave excited near the diffraction grating when the electron velocity is almost equal to the phase velocity of the surface wave. Then, the surface harmonic wave is electromagnetically coupled to a radiation mode. The dynamics of electrons are analyzed quantum mechanically where the electron is represented as a traveling electron wave with a finite spreading length. The conversion of the surface wave into a propagating mode is analyzed using the classical Maxwell's equations. In the small-signal gain regime, closed-form expressions for the contributions of the stimulated and spontaneous emissions to the evolution of the surface wave are derived. The inclusion of the spreading length of the electron wave to the emission spectral line is investigated. Finally, we compare our results based on the quantum mechanical description of electron and those based on the classical approach where a good agreement is confirmed. & 2015 Elsevier B.V. All rights reserved.
منابع مشابه
Collective and Single-Electron Interactions of Electron Beams with Electromagnetic Waves, and Free-Electron Lasers*
The field of radiation emission from electron beams is reviewed with special reference to work related to free-electron lasers. Different schemes o f interaction in periodic structures, electromagnetic slow-wave structures, and in transverse confining force are distinguished. Various effects and devices such as traveling wave amplifiers, Smith-Purcell radiators, Cerenkov and bremsstrahlung-free...
متن کاملNumerical Simulation of Smith-purcell Free Electron Lasers
We present a one-dimensional time-dependent analysis and simulation of Smith-Purcell (SP) free-electron lasers (FELs). The coupled Maxwell-Lorentz equations are set up, and the details of numerical simulation are presented. At low electron beam energy, a SP-FEL is a backward wave oscillator (BWO), and oscillations can be achieved without the need for feedback mirrors. In the linear regime, we s...
متن کاملEffect of Losses on the Gain and Start Current in Smith-purcell Free-electron Lasers
[email protected] Abstract The effect of dissipative losses in the grating surface of a Smith-Purcell free-electron laser is examined analytically. It is shown that losses have a significant impact on the gain of amplifiers (which operate on a convective instability) and on the growth rate of oscillators (which operate on an absolute instability), but it is not absolutely necessary ...
متن کاملEnergy Levels of InGaAs/GaAs Quantum Dot Lasers with Different Sizes
In this paper, we have studied the strain, band-edge, and energy levels of cubic InGaAs quantum dots (QDs) surrounded by GaAs. It is shown that overall strain value is larger in InGaAs-GaAs interfaces, as well as in smaller QDs. Also, it is proved that conduction and valence band-edges and electron-hole levels are size dependent; larger QD sizes appeared to result in the lower recombination...
متن کامل