16:30 〜 16:45
▲ [20p-E206-11] Development of terahertz artificial materials based on the composites of metal-dielectric woven wires
キーワード：Terahertz, artificial materials, metal-dielectric woven wires
Photonic structures found in biology have diverse periodic structures and make animals, insects and plants sensitive to the light with colorful and bright appearances. The fundamental theory shows the photonic bandgap is the intrinsic property of a periodic structure to reflect light waves, which is specified by the pitch size, layer thicknesses and dielectric constants. The reflection or transmission ability of an artificial material can thus be engineered to increase the efficiency of the designed optical devices, such as the reflectors, waveguides, and sensors.
In tradition, semiconductors are the terahertz (THz) artificial materials because plasmonic frequency in THz band can be modified via the intrinsic carrier concentrations. The semiconductor-slab-stacking structures are therefore workable for the THz Bragg reflectors when the critical dielectrics can be designed for each semiconductor slab. However, such artificial materials based on semiconductors are expensive to prepare, not flexible, and have high reflection loss at the input interface due to the high THz refractive indices.
Meta-surface (i.e., metamaterial) based on a periodic metal pattern is another type of THz artificial material when local surface resonance can be realized among the unit pattern cells. However, to fabrication the subwavelength scale metal patterns, the rigid substrate is required in the photolithography, physical/chemical etching and the metal coating processes. Although the meta-surfaces on the polymer substrates have high flexibility, the deformable range and shape are still not acceptable in the applications, such as the waveguides, or absorbers with various shapes or volumes. To efficiently manipulate THz photons/wave at the near-field and remote locations, the cheap, soft and substrate-free artificial materials are urgently requested.
In tradition, semiconductors are the terahertz (THz) artificial materials because plasmonic frequency in THz band can be modified via the intrinsic carrier concentrations. The semiconductor-slab-stacking structures are therefore workable for the THz Bragg reflectors when the critical dielectrics can be designed for each semiconductor slab. However, such artificial materials based on semiconductors are expensive to prepare, not flexible, and have high reflection loss at the input interface due to the high THz refractive indices.
Meta-surface (i.e., metamaterial) based on a periodic metal pattern is another type of THz artificial material when local surface resonance can be realized among the unit pattern cells. However, to fabrication the subwavelength scale metal patterns, the rigid substrate is required in the photolithography, physical/chemical etching and the metal coating processes. Although the meta-surfaces on the polymer substrates have high flexibility, the deformable range and shape are still not acceptable in the applications, such as the waveguides, or absorbers with various shapes or volumes. To efficiently manipulate THz photons/wave at the near-field and remote locations, the cheap, soft and substrate-free artificial materials are urgently requested.