Laser beams with screw dislocations in their wavefronts

Coherent optical vortices from relativistic electron beams

“…Promising applications include expanded x-ray magnetic circular dichroism [9] where angle-resolved energy loss spectrometry distinguishes spin-polarized atomic transitions subject to different photon OAM and polarization states [10]. Traditionally, these "optical vortices" are created by shaping of the phase front of a laser as it passes through different optical media [11][12][13], such as spiral phase plates [14] or computer generated holograms [15]. Analogous techniques have also been used to transform x-rays into vortices at synchrotron light sources [16,17], and alternate methods suggest vortex beams can be created through Compton back-scattering [18] or harmonic emission in undulators [19].…”

Wave beams with orbital angular momentum: a step towards terahertz

“…In physical optics, the spin momentum is described as the polarization of light beams, and the orbital angular momentum (OAM) is the rotation of beam along the azimuth. Interest in beams with OAM [1,2], or "vortex beams," appeared shortly after the creation of lasers and increased after the publication of the article [3]. Vortex beams have been formed and investigated in the spectral range from X-ray to radio waves, but only a few publications are devoted to beams with OAM in the terahertz range (see [4] and references therein).…”

Формирование Оптических Вихрей С Помощью Голограмм С Асимметричным Профилем Штриха

“…Их генерируют преднамеренно [7], получая вихревые пучки на выходе из лазерного резонатора, конвертируя фундаментальный гауссов пучок в вихревой пучок вне лазерного резонатора или применяя когерентную ком-бинацию пучков [8,9]. Во многих случаях конвертором служит фазовая голограмма [10][11][12][13].…”