Fig. 1
From: Long-propagating ghost phonon polaritons enabled by selective mode excitation
Shape-Dependent Micro/Nano Antennas for Asymmetric g-HP Excitation. a–c Experimental near-field images of antenna-launched (disk, rectangle, triangle) g-HPs at the illumination frequency \({\rm{\omega }}=1460{{\rm{cm}}}^{-1}\). d–f Simulated near-field images of antenna-launched (disk, rectangle, triangle) g-HPs. g–i Absolute value of the Fourier transform of the images shown in a–c, the bright spots represent the modes excited, and the white arrows indicate the wave vectors (momenta) of the antenna-launched g-HPs. Green arrows indicate the energy flow direction/group velocity Vg,(i) of the respective polaritonic branch. White dotted curve lines represent the IFC (left and right)
