title: Generation of Terahertz Surface Plasmon Polaritons Using Nondiffractive Bessel Beams with Orbital Angular Momentum.
abstract: Bessel vortex beams with topological charges of l=±1 and l=±2 were produced in the terahertz spectral range from a free electron laser Gaussian beam (λ=141  μm) transformed using silicon binary diffractive optical elements. The spatial characteristics of the beams were obtained using a microbolometer array. A radius to path length ratio of 1:100 was achieved for nondiffractive beams with the average power of 30 W. Surface plasmon polaritons (SPPs) on gold-zinc-sulphide-air interfaces were generated due to diffraction of vortex beams on a sample edge. A new effect, a dependence of the efficiency of SPP generation on the direction of the azimuthal component of incident-radiation Poynting vector, was revealed.
authors.affiliation: Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia.|Novosibirsk State University, 630090 Novosibirsk, Russia.
authors.forename: B A
authors.initials: BA
authors.lastname: Knyazev
authors.affiliation: Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia.|Novosibirsk State University, 630090 Novosibirsk, Russia.
authors.forename: Yu Yu
authors.initials: YY
authors.lastname: Choporova
authors.affiliation: Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia.|Novosibirsk State University, 630090 Novosibirsk, Russia.|Novosibirsk State Technical University, 630073 Novosibirsk, Russia.
authors.forename: M S
authors.initials: MS
authors.lastname: Mitkov
authors.affiliation: Samara State Aerospace University, 443086 Samara, Russia.|Image Processing Systems Institute RAS, 443001 Samara, Russia.
authors.forename: V S
authors.initials: VS
authors.lastname: Pavelyev
authors.affiliation: Samara State Aerospace University, 443086 Samara, Russia.
authors.forename: B O
authors.initials: BO
authors.lastname: Volodkin