Edge effects on plasmonic nanolithography

Recently, surface plasmon lithography has been developed as a promising parallel route to overcome the diffraction limit. Several schemes, such as surface plasmon through apertures on mask or surface plasmon interference have been successfully demonstrated for performing nearfield photolithography that does not require short-wavelength light. During the experiment, in order to obtain reasonable exposed patterns, we added a protection layer on the bottom side of the metallic mask to get rid of the edge effect.