fig 1 (IMAGE) Compuscript Ltd Caption Figure 1. The forbidden propagation of hyperbolic phonon polaritons. (a) Dispersion and corresponding Im(rp) of PhPs in a 100-nm-thick α-MoO3 slab for air (a) and (c), SiC (b), and Au (d) substrates at different frequencies. At an incident frequency of 936 cm−1, the principal axis of the hyperbola-like curves lays along the [100] direction (a) while it is along [001] direction (b) when adopting SiC substrate. The blue and yellow curves present l = 0 and l = 1 modes, respectively. (e–h) The simulated near-field distribution, Re (Ez), is excited by an electric dipole on the α-MoO3 slab. The insets are the corresponding dispersions obtained by the Fourier transform of the electric distribution Re (Ez) Credit OES Usage Restrictions Credit must be given to the creator. License CC BY Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.