  We fabricate and characterize waveguides composed of closely spaced and
longitudinally oriented silicon ridges etched into silicon-on-insulator wafers.
Through both guided mode and bulk measurements, we demonstrate that the
patterning of silicon waveguides on such a deeply subwavelength scale is
desirable for nonlinear and sensing applications alike. The proposed waveguide
geometry simultaneously exhibits comparable propagation loss to similar schemes
proposed in literature, an enhanced effective third-order nonlinear
susceptibility, and high sensitivity to perturbations in its environment.
