Open AccessBessel terahertz imaging with enhanced contrast realized by silicon multi-phase diffractive optics
Author(s) -
Linas Minkevičius,
Domas Jokubauskis,
Irmantas Kašalynas,
Sergej Orlov,
Antanas Urbas,
Gintaras Valušis
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.036358
Subject(s) - optics , terahertz radiation , axicon , materials science , bessel beam , silicon , diffraction , bessel function , phase contrast imaging , laser , physics , optoelectronics , phase contrast microscopy , laser beams
Bessel terahertz (THz) imaging employing a pair of thin silicon multi-phase diffractive optical elements is demonstrated in continuous wave mode at 0.6 THz. A proposed Bessel zone plate (BZP) design - discrete axicon containing 4 phase quantization levels - based on high-resistivity silicon and produced by laser ablation technology allowed to extend the focal depth up to 20 mm with minimal optical losses and refuse employment of bulky parabolic mirrors in the imaging setup. Compact THz imaging system in transmission geometry reveals a possibility to inspect objects of more than 10 mm thickness with enhanced contrast and increased resolution up to 0.6 of the wavelength by applying deconvolution algorithms.