Nano-plasmonic dual-mode probe for near-vector field scanning optical microscopy

The probe serves as a pivotal component in scanning near-field optical microscopy, enhancing its imaging resolution by capturing high-frequency information within the sample's near-field region. However, a current limitation exists: a single probe can only respond to either the transverse or longitudinal vector field independently. This single polarization response not only escalates imaging costs but also leads to a loss of imaging information, thereby narrowing the application scope of scanning near-field microscopy. In this work, we propose a nano-plasmonic probe that has two transmission modes and can characterize the transverse and longitudinal near-fields using a single system. The proposed nano-plasmonic probe has a nanoparticle-on-aperture in the film structure that is designed on a tapered fiber tip. Finally, the feasibility of the fabrication of the nano-plasmonic probe using optical tweezers technology is analyzed and studied. This nano-plasmonic probe shows great potential for use in near-field optical microscopy applications.