Fig. 1. Sub-wavelength metallic groove array in metallic substrate and coordinate system

Fig. 2. Enhancement factor as a function of groove depth and array period at the rabbet of sub-wavelength groove array in gold substrate. (a) w=0.01λ; (b) w=0.1λ

Fig. 3. Average effect of Raman scattering enhancement factor as a function of Λ in sub-wavelength groove array in gold substrate

Fig. 4. EF(0,z) as a function of the vertical distance z for groove arrays in gold substrate with different groove widths

Fig. 5. Enhancement factor EF as a function of period Λ for different noble metal types