THz characterization of low-conductive sheet-charges with metallic gratings

We study the application of metallic gratings with subwavelength apertures to characterize sheet charges of very low conductivity (similar to mu Sie) in a transmission geometry. The gratings provide increased E-field enhancement and interaction length in the vicinity of the aperture which allows for enhanced absorption by the two-dimensional sheet charges, which would otherwise be undetectable in a transmission measurement. We explore the design space to obtain both broadband and resonant behavior by altering the pitch of the gratings (w.r.t. lambda) in order to be applicable for both characterization and device applications.