Nano-apertures vs. nano-barriers: Surface scanning through obstacles and super-resolution in AFM-NSOM dual-mode

Abstract

As part of the performance characterization of a combined and enhanced new AFM-NSOM tip-photo-detector, diffraction limitations were studied on two complementary samples: a nano-barrier embedded between two nano-apertures and one nano-aperture embedded between two nano-barriers. These consecutive multiple-obstacle scanning paths are part of this challenging specifications study of a new conical-shaped and drilled tip-photodetector, sharing a subwavelength aperture. A super-resolution algorithm feature was added in order to overcome possible obstacles, while scanning the same object with several small angles. The new multi-mode system includes scanning topography, optical imaging and an obstacle-overcoming algorithm. The present article study emphasizes the complexity of nano-scanning multiple-apertures/barriers. Both complementary analytical (Python) and numerical (Comsol) analyses are presented to forecast the expected scanning behavior and limitations. Moreover, in addition to a new concept of a combined AFM-NSOM drilled photo-sensor tip, several breakthroughs are presented in the algorithm itself: treatment of one unique pixel, angular scanning and reconstruction of sub-wavelength information. The uniqueness of the present study lies in its provision of a comprehensive solution to near field scanning: a paired hardware and software package solution.