Super-resolution plasmonic imaging microscopy for a submicron tracking emulsion detector

Abstract

A Nano Imaging Tracker (NIT) is a super-fine-grained nuclear emulsion that is capable of detecting an ionizing particle with nanometric resolution and recording the track by a line of silver nanograins of various shapes and sizes. The particle tracks need to be read out by some microscopic techniques; here we focus on the optical response of silver nanograins to realize a readout method beyond the diffraction limit. In this paper, super-resolution plasmonic imaging microscopy (SRPIM), which utilizes the polarization-dependent optical response due to the localized surface plasmon resonance (LSPR) is developed. A spatial resolution of 4.7 $\pm$ 0.1 nm for SRPIM to identify the nanograin position is achieved. We show that SRPIM clearly discriminates 100 keV carbon ion tracks with a mean range of 270 nm from single nanograins with a diameter of 60 nm. The recognition efficiency of the 100 keV carbon track was $49\pm 4\%$ and the angular resolution was $17\pm 2^\circ$.