Generation of limited-diffractive twisted pulses at millimeter waves

In this paper, the generation of twisted pulses carrying orbital angular momentum is discussed. Such pulses are generated by polychromatic superposition of higher-order Bessel beams. The non-negligible effect of the wavenumber frequency-dispersion on the pulse propagation at millimeter waves is taken into account. Large operating bandwidths are required to synthesize spatially confined electromagnetic pulses. For this reason, a wideband Bessel-beam launcher is proposed, implementing an inward cylindrical traveling-wave aperture distribution with an azimuthal phase variation. Preliminary results clearly show the possibility of successful generation of twisted electromagnetic pulses at millimeter waves.