SILICON DIFFRACTIVE OPTICAL ELEMENTS FOR HIGH-POWER MONOCHROMATIC TERAHERTZ RADIATION
A. N. Agafonov1, B. O. Volodkin1, A. K. Kaveev2, B. A. Knyazev3,4, G. I. Kropotov2, V. S. Pavel’ev1,5, V. A. Soifer1,5, K. N. Tukmakov1, E. V. Tsygankova2, Yu. Yu. Choporova3,4
1Korolev Samara State Aerospace University, Moskovskoe Shosse 34, Samara, 443086 Russia
andr_agafonov@mail.ru
2Tydex company, ul. Domostroitel’naya 16, St. Petersburg 194292, Russia
andreykaveev@tydex.ru
3Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent’eva 11, Novosibirsk, 630090 Russia
knyazev@inp.nsk.su
4Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia
yulia.choporova@inp.nsk.su
5Image Processing Systems Institute, Russian Academy of Sciences, ul. Molodogvardeiskaya 151, Samara, 443001 Russia
nano@ssau.ru
Keywords: DOE, terahertz radiation
Abstract
This paper presents a fabrication technique and results of studies of silicon binary diffractive optical elements (DOEs): a diffractive lens and a 1 : 2 diffractive beam splitter with an aperture diameter of 30 mm for the terahertz spectral range. The elements were fabricated in two versions: with and without an antireflection coating of parylene C. The DOE characteristics were investigated in the beam of the Novosibirsk free electron laser at a wavelength of 141 µm. The results are given of a study of the radiation resistance of the coating, which remained intact upon exposure to an average radiation power density of 4 kW/cm2; the peak power in a 100 ps pulse was almost 8 MW/cm2. Experimental estimates of the diffraction efficiency of the elements coated with the antireflection coating are in good agreement with theoretical estimates.
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