Plasmonic nanograting tip design for high power throughput near-field scanning aperture probe.

We design nanogratings consisting of concentric plasmonic resonance grooves on the metallic sidewalls of near-field scanning probe aperture to increase the power throughput without losing the imaging resolution. Nanograting tip design involves choosing the proper pitch length and the cut location of grooves. Four different nanograting designs are evaluated, as compared with standard single aperture pyramidal near-field scanning probe without grating patterns. We show that, by adding nano-grooves at the location of electromagnetic field intensity-maximum along interface and with the pitch period matching the surface plasmon wavelength, the power throughput can be greatly increased by at least a factor of 530 at 405nm UV wavelength with 100nm diameter aperture probe.