Localized Field Enhancements in Guided and Defect Modes of a Periodic Slot Waveguide

We present a periodic slot waveguide for achieving enhanced light–matter interaction that provides significant localized field and power density enhancements over traditional slot waveguides. The basic structure is based on a slot waveguide with 1-D periodic holes. The slot effect provides strong field enhancement and subwavelength confinement, and the periodicity of the structure is exploited to locally magnify or “pinch” the electric field distribution, resulting in additional enhancements. Characteristics of the modes presented by this structure are examined by finite-difference time-domain (FDTD) modeling. Distinct optical gradients and localized
$\vert{\rm E}\vert^{2}$
enhancements, which are up to
$\sim$
4–5 times greater than comparable slot waveguides, can be achieved. Potential application of the periodic slot waveguide structure to fields, including optical manipulation, sensing, and nonlinear or active material integration, is discussed.