Terahertz Optics of Materials with Spatially Harmonically Distributed Refractive Index

Dzmitry Bychanok; Gleb Gorokhov; Artyom Plyushch; Alfredo Ronca; Marino Lavorgna; Hesheng Xia; Patrizia Lamberti; Polina Kuzhir

doi:10.3390/ma13225208

Terahertz Optics of Materials with Spatially Harmonically Distributed Refractive Index

Materials (Basel). 2020 Nov 18;13(22):5208. doi: 10.3390/ma13225208.

Authors

Dzmitry Bychanok^{1

2}, Gleb Gorokhov^{1

3}, Artyom Plyushch^{1

3}, Alfredo Ronca⁴, Marino Lavorgna⁴, Hesheng Xia^{4

5}, Patrizia Lamberti⁶, Polina Kuzhir^{1

7}

Affiliations

¹ Research Institute for Nuclear Problems Belarusian State University, Bobruiskaya str. 11, 220030 Minsk, Belarus.
² Radioelectronics Department, Faculty of Radiophysics, Tomsk State University, 36 Lenin Prospekt, 634050 Tomsk, Russia.
³ Faculty of Physics, Vilnius University, Sauletekio 3, LT-10222 Vilnius, Lithuania.
⁴ Institute of Polymer, Composite and Biomaterials, National Research Council, Via G.PreViati, 1/E, 23900 Lecco, Italy.
⁵ State Key Laboratory of Polymer Materials Engineering, Polymer Research Institute, Sichuan University, Chengdu 610065, China.
⁶ Dept. of Information and Electrical Engineering and Applied Mathematics, University of Salerno, Via Giovanni Paolo II, 132-84084 Fisciano (SA), Italy.
⁷ Institute of Photonics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland.

Abstract

The electromagnetic properties of structures with spatially periodic distributed graded refractive index were investigated in the terahertz frequency range. The band structure and electromagnetic response of material with harmonically distributed refractive index were calculated and analyzed. The analytical expressions for frequencies of the first and second bandgap are derived. 3D printed gyroid based architectures were proven to be harmonically graded refractive index structures with designed bandgaps in THz frequency ranges. The transmission coefficient of thermoplastic polyurethane-based samples were experimentally measured in the frequency range 100-500 GHz and compared with theoretical results. Due to losses in the real world produced samples, the predicted response is significantly dumped in the terahertz range and only traces of band gaps are experimentally observed. This funding paves the way toward a new generation of 3D printed THz components for gradient-index optics applications.

Keywords: graded index materials; harmonically distributed refractive index; terahertz bandgap.

Abstract

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