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JOURNALS // Optics and Spectroscopy // Archive

Optics and Spectroscopy, 2018 Volume 124, Issue 3, Pages 420–428 (Mi os1058)

This article is cited in 7 papers

Geometric and applied optics

Wide-aperture aspheric optics for formation of subwavelength caustics of a terahertz electromagnetic-radiation beam

N. V. Chernomyrdinab, A. O. Schadkoa, S. P. Lebedevc, I. E. Spektorc, V. L. Tolstoguzova, A. S. Kucheryavenkoa, K. M. Malakhova, G. A. Komandinc, V. S. Gorelikd, K. I. Zaitsevacb

a Bauman Moscow State Technical University, Moscow, 105005, Russia
b I. M. Sechenov First Moscow State Medical University
c A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, 119991, Russia
d P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119333, Russia

Abstract: A wide-aperture aspheric lens for focusing a terahertz electromagnetic-radiation beam in a circle of the subwavelength size is proposed. The calculation of the lens and the estimation of size of created caustic were carried out using computational methods of geometric optics and electrodynamics. The lens is made of high-density polyethylene with the help of a turning machine. For experimental estimation of the spatial resolution provided by the lens, a THz imaging system based on raster scanning of the object's surface was created. The imaging system was used in combination with wide-aperture THz optics to record images of the streak plates with different spatial frequencies. Analysis of the experimental data showed that the aspheric lens allows the resolution of two objects spaced at a distance of 0.95$\lambda$, providing contrast of 15%. The proposed THz optics is superior to classical THz spherical lenses and off-axis parabolic mirrors, greatly expanding the capabilities of THz-spectroscopy methods and imaging.

Received: 26.10.2017

DOI: 10.21883/OS.2018.03.45664.250-17


 English version:
Optics and Spectroscopy, 2018, 124:3, 428–436

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