Fig. 2: Near-field imaging of polariton evolution in a hBN metasurface.

a Schematic of the near-field nanoimaging experiment. b, c Near-field images measured at two different frequencies, ω = 1415 cm⁻¹ (HPhP region) and ω = 1510 cm⁻¹ (EPhP region). White arrows indicate the polariton fringes observed on the metasurface.