Terahertz Optics of Materials with Spatially Harmonically Distributed Refractive Index

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.

The biological effects of terahertz wave radiation-induced injury on neural stem cells

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Behavioral Effect of Terahertz Waves in C57BL/6 Mice

“…THz waves are located in a unique band in the entire electromagnetic spectrum [ 1 , 2 ]. In recent years, with the continuous development of terahertz technology, it has been gradually studied and applied in various fields: remote sensing radar [ 3 ], material structure detection [ 4 ], data transmission [ 5 ], communication [ 6 ], security [ 7 ], and counter-terrorism [ 8 ]. In biomedicine, THz waves have the characteristics of low energy and non-ionizing radiation, and it will not cause harmful damage to biological tissues or organisms [ 9 , 10 ]; therefore, THz are used to identify and distinguish various biological small molecules [ 11 ], macromolecules [ 12 , 13 , 14 ], biological information extraction [ 15 ], and drug component detection [ 16 ].…”