A nanoplasmonic probe for near-field imaging.

We demonstrate a nanoplasmonic probe that incorporates a subwavelength aperture coupled to a fine probing tip. This probe is used in a hybrid near-field scanning optical microscope and atomic force microscope system that can simultaneously map the optical near-field and the topography of nanostructures. By spatially isolating but optically coupling the aperture and the localizing point, we obtained near-field images at a resolution of 45 nm, corresponding to λ/14. This nanoplasmonic probe design overcomes the resolution challenges of conventional apertured near-field optical probes and can provide substantially higher resolution than demonstrated in this work.