Full text loading...
The polarization is defined in reference to the orientation of the nanotrenches.
The dispersion relation, calculated from the metal-insulator-metal model using interpolated optical constants from Ref. 6, shows large wave vectors accessible in very narrow trenches.
Complete absorption in aluminum and gold nanotrenches tuned for conventional laser wavelengths. The dimensions were calculated using RCWA code and verified using FDTD methods (see Refs. 7 and 8). Note that the minor reflectivity dips corresponding to the grating plasmon (due to the periodicity of the nanotrenches) are clearly visible in gold. The s-polarized reflectivity response is equivalent to that of a flat surface metal.
Field enhancement for a nanotrench with , , and in gold. The comparison between s- and p-polarized light at 600 nm shows the extreme polarization selectivity of the nanotrenches.
The nanolithography steps are: (a) the e-beam resist, HSQ, is patterned on the silicon substrate creating a template, (b) the gold is evaporated onto the template, and (c) the template is removed in the KOH bath. The cross section of the resulting structure is shown in (d).
Reflectivity of a nanotrench surface. is the ratio of the reflectivity with the E vector perpendicular and parallel to the trenches. The dots show data and the solid line shows the results of a FDTD simulation, using the measured average shape of the trenches; the top inset shows the dashed geometry of the nanotrenches. The bottom inset shows a reflectivity image of the patterned sample with light polarized parallel (top half) and perpendicular (bottom half) to the trenches; the dashed lines outline the total patterned area.
Article metrics loading...