The concept of adiabatic mode transformation between silicon waveguide and surface plasmon-polariton modes in subwavelength metal-dielectric slots is investigated. The mode transformer consists of a modulated-index slot region, which is bound by two metal slabs. Using the design scheme, we will show that the optical dispersion of a modulated-index metal slot waveguide can be engineered well above the silicon light-line on a large wavelength region, allowing direct phase-matching between surface plasmon polaritons and traditional waveguide modes. Based on full-field, finite difference simulations, we demonstrate that reversible mode conversion can be achieved within submicrometer length scales.
© 2007 Optical Society of America
Original Manuscript: May 31, 2007
Revised Manuscript: September 5, 2007
Manuscript Accepted: September 9, 2007
Published: October 18, 2007
Ning-Ning Feng and Luca Dal Negro, "Plasmon mode transformation in modulated-index metal-dielectric slot waveguides," Opt. Lett. 32, 3086-3088 (2007)