Fig. 3
From: Source-configured symmetry-broken hyperbolic polaritons
Experimental observation of the tunable symmetry of antenna-launched HPs in calcite. a Schematic of the near-field polariton-launching experiment. (b) Near-field image displaying the dipolar electric field distributions on gold disk antenna. The center of positive and negative phases is denoted by + and − , respectively. The polarization direction of the gold disk antenna is indicated by a double-headed arrow. c,d Experimental near-field amplitude |Ein + Ep|. c and near-field distribution with background subtracted |Ep|. d of the antenna-launched HPs at various values of φ. The illuminating frequency was 1470 cm−1. The extremity of the gold disk is highlighted by yellow circles. e Experimental (solid curves) and simulated (dashed curves) amplitude profiles |Ep| extracted along dashed line in d (cf. Additional file 1: Fig. S10b). ΔS represents the difference in electric field peak intensities for two rays of different direction. f Normalized ΔS as a function of φ