Abstract-Generation of Terahertz Surface Plasmon Polaritons Using Nondiffractive Bessel Beams with Orbital Angular Momentum

B. A. Knyazev, Yu. Yu. Choporova, M. S. Mitkov, V. S. Pavelyev, and B. O. Volodkin

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.163901

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.

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