Abstract-Flexible materials for terahertz optics: advantages of graphite-based structures

Rusnė Ivaškevičiūtė-Povilauskienė, Linas Minkevičius, Domas Jokubauskis, Andrzej Urbanowicz, Simonas Indrišiūnas, and Gintaras Valušis

 THz-TDS transmittance spectra and insets depict THz-CW two-dimensional THz beam profiles focused with a) metal TZP; b) graphite foil TZP; c) graphite on paper TZP; d) pure paper TZP. The beam cross sections at the maximum intensity are presented in a linear scale as a solid black line for each case. Maximum signal amplitude of the TZPs is normalized to the maximum amplitude of the unfocused beam.

https://www.osapublishing.org/ome/abstract.cfm?uri=ome-9-11-4438

Flexible materials for applications in terahertz (THz) range imaging systems are investigated in this study. THz time-domain spectroscopy and THz imaging at 0.6 THz frequency are used to analyze optical properties of zone plates (TZP) with integrated cross-shaped filters, which are fabricated using direct laser writing on thin graphite, HB pencil-shaded graphite on paper, as well as reference metal-based and pure paper zone plates. Spectral features and focusing power comparable to the best metal-based TZP is achieved with graphite-based TZP. The pure paper and paper with pencil-shaded graphite TZPs showed increase in focusing power by a factor of ∼1.5, supporting numerical 3D finite-difference time-domain simulations. The findings show that graphite-based TZPs can serve as a flexible, compact, and inexpensive optics elements for emerging THz imaging systems.

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