Abstract

Dual-tip scanning near-field optical microscopy (SNOM) facilitates high-precision spatial positioning of a point-like emitter and detector and has the capability of mapping optical near-field information very close to the dipole-like excitation. Hence, it opens new opportunities to characterize the optical near-field response of subwavelength photonic structures. Here we show that by using a fully automated dual-tip SNOM [1] the local field response of a metasurface, consisting of silicon nanodiscs [2] becomes accessible. In our measurements, one tip of the SNOM excited a single resonant nanodisc of sub-wavelength size, whereas the second tip mapped the near-field of the surrounding discs excited via in-plane coupling.

© 2019 IEEE