Greatly enhanced continuous-wave terahertz emission by nano-electrodes in a photoconductive photomixer

H. Tanoto, J. H. Teng, Q. Y. Wu, M. Sun, Z. N. Chen, S. A. Maier, B. Wang, C. C. Chum, G. Y. Si, A. J. Danner, S. J. Chua

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An efficient, room-temperature-operation continuous-wave terahertz source will greatly benefit compact terahertz system development for high-resolution terahertz spectroscopy and imaging applications. Here, we report highly efficient continuous-wave terahertz emission using nanogap electrodes in a photoconductive antenna-based photomixer. The tip-to-tip nanogap electrode structure provides strong terahertz field enhancement and acts as a nano-antenna to radiate the terahertz wave generated in the active region of the photomixer. In addition, it provides good impedance-matching to the terahertz planar antenna and exhibits a lower RC time constant, allowing more efficient radiation, especially at the higher part of the terahertz spectrum. As a result, the output power of the photomixer with the new nanogap electrode structure in the active region is two orders of magnitude higher than for a photomixer with typical interdigitated electrodes. The terahertz emission bandwidth also increases by a factor of more than two.

Original languageEnglish
Pages (from-to)121-126
Number of pages6
JournalNature Photonics
Issue number2
Publication statusPublished - Feb 2012
Externally publishedYes

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