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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 16 — Aug. 3, 2009
  • pp: 13502–13515

Enhancement of optics-to-THz conversion efficiency by metallic slot waveguides

Zhichao Ruan, Georgios Veronis, Konstantin L. Vodopyanov, Marty M. Fejer, and Shanhui Fan  »View Author Affiliations

Optics Express, Vol. 17, Issue 16, pp. 13502-13515 (2009)

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A metallic slot waveguide, with a dielectric strip embedded within, is investigated for the purpose of enhancing the optics-to-THz conversion efficiency using the difference-frequency generation (DFG) process. To describe the frequency conversion process in such lossy waveguides, a fully-vectorial coupled-mode theory is developed. Using the coupled-mode theory, we outline the basic theoretical requirements for efficient frequency conversion, which include the needs to achieve large coupling coefficients, phase matching, and low propagation loss for both the optical and THz waves. Following these requirements, a metallic waveguide is designed by considering the trade-off between modal confinement and propagation loss. Our numerical calculation shows that the conversion efficiency in these waveguide structures can be more than one order of magnitude larger than what has been achieved using dielectric waveguides. Based on the distinct impact of the slot width on the optical and THz modal dispersion, we propose a two-step method to realize the phase matching for general pump wavelengths.

© 2009 Optical Society of America

OCIS Codes
(190.4390) Nonlinear optics : Nonlinear optics, integrated optics
(230.7370) Optical devices : Waveguides

ToC Category:
Nonlinear Optics

Original Manuscript: May 5, 2009
Revised Manuscript: June 16, 2009
Manuscript Accepted: June 18, 2009
Published: July 22, 2009

Zhichao Ruan, Georgios Veronis, Konstantin L. Vodopyanov, Marty M. Fejer, and Shanhui Fan, "Enhancement of optics-to-THz conversion efficiency by metallic slot waveguides," Opt. Express 17, 13502-13515 (2009)

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