Fig. 1: Real-space imaging of HShPs launching from infrared antenna on the surface of bGO observed via FEL-coupled s-SNOM.
From: Controlling the propagation asymmetry of hyperbolic shear polaritons in beta-gallium oxide
a Schematic of FEL-coupled near-field imaging experiment. b Experimental near-field image of HShPs launched by a 2 µm gold disc by the incident FEL beam (oriented along the dashed white line) at a frequency of 712 cm−1. c and d Finite element modeling of HShP launched by a 2 µm gold disc under similar launching conditions to the experiment shown in (b), in real-space (c) and Fourier space (d). Red dashed curves denote the dispersion of HShPs calculated from theory (Supplementary Note S1). The white arrows indicate the clockwise redistribution of intensity along each branch of the dispersion causing the asymmetry we observe in the momentum map, see Supplementary Fig. 3 for details.
