Electron diffraction on a traveling wave: “Inelastic Kapitza–Dirac effect”

Abstract

In this paper conceptual points regarding electrons elastic (Kapitza-Dirac effect) and inelastic diffraction effect on the different type slowed electromagnetic wave structures/light gratings are considered. From the unified point of view it is analyzed the main works on this subject for last four decades in chronological order, pointing out the essential peculiarity inherent in induced Cherenkov, Compton, and undulator/wiggler processes too. This review article has also a goal to resolve confusion in scientific literature connected with the recently appeared paper [6] relating the electrons diffraction on a traveling wave in a dielectric medium.In recent years, especially after the realization of experiment on strongly coherent and intense laser beams [1], the interest to Kapitza-Dirac effect [2] has been increased. This, in particular, is conditioned by the significant role of observed electrons diffraction effect on highintensity laser beams-gratings [3], [1], since the diffracted from highly coherent laser gratings electron beams are coherent with each other, and Kapitza-Dirac effect is a very convenient, perhaps the best means to realize coherent electron beams (see, also, the review paper [4]). This is important fact that can serve as a basis for construction of diverse type new tools, e.g., coherent beam splitters, new type electron interferometers which would operate at rather low electron energies etc. Furthermore, since 1975 the scope of the Kapitza-Dirac effect, which is valid for the electrons elastic scattering on a standing light wave/grating, has been extended [7], [8], [9] for inelastic diffraction scattering of electrons on a slowed travelling wave propagating with the phase velocity v ph < c (c is the light speed in vacuum), to consideration of general aspects of which is devoted the present review article. The motivation of the latter have two reasons. First -that is the most important, is connected with the essential peculiarity inherent in mentioned processes (induced Cherenkov, Compton, and undulator/wiggler) [7], [8], [9] -existence of a critical field, above which a nonlinear threshold phenomenon arises radically changing the dynamics of electron-slowed travelling wave interaction, and consequently, the situation for inelastic diffraction scattering. Second, electrons diffraction effect on a travelling wave in a dielectric medium requires a special consideration because of a confusion in scientific literature connected with the appearance recently of a paper on this subject [6]. Therefore, apart from the pure scientific interest, the current review has a goal to clear up the-state-of-the-art in the considering field for last four decades in chronological order, to avoid the further confusion and misunderstandings in scientific literature.The predicted by Kapitza and Dirac in 1933 phenomenon of electrons diffraction scattering on a phase lattice of a standing light wave naturally for that time had an one-photon character because of the absence of strong and coherent radiation fields. The e...

On a quantum particle in laser channels

“…Neglecting the last term in eq. ( 2.4) brings us to a known eikonal approximation, which is used, for instance, in the paper [6]. However, in this case we a priori exclude the singularities of the effective potential as a function of longitudinal particle velocity.…”

“…For instance, classical motion of a charged particle in standing laser wave has been deeply analyzed in the work [2], while in our paper [3] the effective potential describing the classical particle trajectory in a laser lattice of arbitrary geometry has been derived. Many papers were devoted to the quantum description of particle interaction in nonuniform electromagnetic fields for both nonrelativistic and relativistic cases (see in [4][5][6] and refs. therein).…”

Relativistic Classical and Quantum Nonlinear Phenomena in the Induced Processes on Free Electrons

“…one can neglect the term ∼ Γ s C s (t) in Eqs. (95) and the dynamics of electron in the wavefields will be described by the following equation [175]:…”

“…Formula (101) for Cherenkov diffraction in a dielectric medium, which had been received forty years ago [108] and included in the monographs [26] and [33], recently has been considered in the paper [175] because of reproduction of electron diffraction effect on a travelling EM wave in a dielectric medium by the authors of the paper [171], nevertheless represented it as a new phenomenon predicted in the paper [171]. Repeating the results of the paper [108] with the main formula (101) in other way of derivation -within the Helmholtz-Kirchhoff diffraction theory (as was mentioned in Introduction, by the method developed in the paper [172]), authors report in the Abstract that they showed on the possibility of electrons diffraction effect on a travelling EM wave in a dielectric medium.…”