Generation of Optical Vortices by Nonlinear Inverse Thomson Scattering at Arbitrary Angle Interactions

Abstract

We theoretically verify that optical vortices carrying orbital angular momentum are generated in various astrophysical situations via nonlinear inverse Thomson scattering. Arbitrary angle collisions between relativistic electrons and circularly polarized strong electromagnetic waves are treated. We reveal that the higher harmonic components of scattered photons carry well-defined orbital angular momentum under a specific condition that the Lorentz factor of the electron is much larger than the field strength parameter of the electromagnetic wave. Our study indicates that optical vortices in a wide frequency range from radio waves to gamma-rays are naturally generated in environments where high-energy electrons interact with circularly polarized strong electromagnetic waves at various interaction angles. Optical vortices should be a new multi-messenger member carrying information concerning the physical circumstances of their sources, e.g., the magnetic and radiation fields. Moreover, their interactions with matter via their orbital angular momenta may play an important role in the evolution of matter in the universe.

Probability of radiation of twisted photons by cold relativistic particle bunches

“…in accordance with the strong addition rule. When the coherent contribution is suppressed, we obtain ρ ≈ 1 , in agreement with the sum rule (35). In order to observe an intense forward coherent radiation generated by a helical bunch in undulators, it is necessary that harmonics (93) overlap with the corresponding harmonics of the undulator radiation [30,34,79] Lorentz factor is γ = 500, the undulator strength parameter is K = 5, and the undulator period is λ0 = 2 cm.…”

“…The first one is the forward radiation of an ideal helical wiggler with the helicity χ = ±1 or the forward radiation produced by charged particles in the laser wave with circular polarization and smooth envelope. In this case, the radiation of twisted photons by one particle obeys the selection rule m = χn [4,5,7,8,10,17,[28][29][30][33][34][35], where n is the harmonic number of radiation. Hence, the probability of incoherent radiation produced by a bunch of particles at the n-th harmonic takes the form…”

“…9. For ζ = −1, the radiation spectrum of the forward radiation is given by [28,29,34,35] k 0 ≈ Ωn las υ 2…”

Semiclassical probability of radiation of twisted photons in the ultrarelativistic limit

“…The hard twisted photons can be employed to study the properties of nuclear matter by exciting higher multipole transitions in nuclei and hadrons (see, e.g., the discussion in [24,25,41,42]). Rather recently, it was shown that hard twisted photons can be generated in channeling radiation [43,44] and strong laser pulses [41,[45][46][47][48]. In Sec.…”

Probability of radiation of twisted photons in an inhomogeneous isotropic dispersive medium

“…It turns out that a charged particle moving uniformly along the helix axis of such a medium is a pure source of twisted photons. Its radiation obeys the selection rules that are pertinent to ideal helical undulators [54,[73][74][75][76][77][78][79][80][81][82][83] or to scattering on helical targets [82]. This fact has a simple explanation in terms of transition scattering of the permittivity wave on the charged particle.…”