Spectrum of spatial frequency of terahertz vortex Bessel beams formed using phase plates with spiral zones

摘要: This paper presents the first numerical and experimental investigation into angular spectrum of terahertz Bessel beam with orbital momentum generated by a phase plate spiral zones. The was exposed to Gaussian Novosibirsk free electron laser. formed passed through collecting lens. distribution intensity radiation wavelength 141 microns before after focusing lens recorded microbolometer array, which moved along optical axis motorized translation stage. experimentally measured distributions over cross section are in good agreement calculations.