Fig. 6: Calculated optical properties of computer-generated and experimentally measured nanosponge geometries.
a, d Calculated absorption a, b and scattering c, d cross sections of reference and phase-field sponges. Shown are spectra of coarse-pored (a, c) and fine-pored (b, d) sponges. Shown in the insets of (a, d) are images of the time-averaged field enhancement distribution ∥E∥/E0 on the sponge surface where it exceeded a factor of 5, as well as ∥E∥/E0 in the surrounding volume where it exceeded a factor of 3, showing the dipole-like nature of the underlying mode. In the top-left and top-right insets, the volume plots are purposefully left out to better show the field enhancement around the excited hot spots. e–h Comparison of the time-averaged field enhancement distribution ∥E∥/E0 between reference and simulated sponges. Shown are the sponges (e) Sc,ref, (f) Sc,2, (g) Sf,ref and (h) Sf,1. The sponge itself is rendered in gray, while the field enhancement is overlaid in regions where it exceeded a factor of 5. The color bar is truncated at 50 and identical in all figures as shown on the right.
