Electro-optic detection of subwavelength terahertz spot sizes in the near field of a metal tip

Journal article (2002)
Department
Imaging Science and Technology (AS) (TU Delft)
Copyright: © 2002 The Author(s); American Institute of Physics
DOI: https://doi.org/doi:10.1063/1.1503404
III-V semiconductors Gallium compounds Electro-optical effects Submillimetre wave imaging Image resolution
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Published Date

26-08-2002

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Source:

Applied Physics Letters, 81 (9), 2002

ISSN:

0003-6951

ISBN:

0003-6951

Source:

http://link.aip.org/link/APPLAB/v81/i9/p1558/s1

Faculty

Applied Sciences

Department

Imaging Science and Technology

Abstract

We report on a method to obtain a subwavelength resolution in terahertz time-domain imaging. In our method, a sharp copper tip is used to locally distort and concentrate the THz electric field. The distorted electric field, present mainly in the near field of the tip, is electro-optically measured in an (100) oriented GaP crystal. By raster scanning the tip along the surface of the crystal, we find the smallest THz spot size of 18 ?m for frequencies from 0.1 to 2.5 THz. For our peak frequency of 0.15 THz, this corresponds to a resolution of ?/110. Our setup has the potential to reach a resolution down to a few ?m.