We demonstrate terahertz (THz) near-field imaging using resonantly enhanced transmission of THz-wave radiation (λ ∼ 200μm) through a bull's eye structure (a single subwavelength aperture surrounded by concentric periodic grooves in a metal plate). The bull's eye structure shows extremely large enhanced transmission, which has the advantage for a single subwavelength aperture. The spatial resolution for the bull's eye structure (with an aperture diameter d = 100 μm) is evaluated in the near-field region, and a resolution of 50 μm (corresponding to λ/4) is achieved. We obtain the THz near-field images of the subwavelength metal pattern with a spatial resolution below the diffraction limit.
|ジャーナル||Japanese Journal of Applied Physics, Part 2: Letters|
|出版ステータス||Published - 2005|
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