Fig. 2

Schematic illustration of the fabrication steps for the proposed MIM waveguide containing a hexagonal cavity with a rectangular bottom slit: (a) Si substrate; (b) spin-coating of the resist layer; (c) nanoimprint lithography for pattern definition; (d) O2 plasma etching to transfer the cavity geometry; (e) electron-beam evaporation of the Ag film; and (f) lift-off to form the final MIM structure.