Figure 1: (a) The refractive index of the NRM slab. The red and blue lines show the real and imaginary parts of the refractive index , respectively. The frequency is  s−1, where [15]. (b) and are not strictly antiparallel ( ) in the lossy NRM slab, featuring the “walk-off” angle about at , at , and at . The carrier frequency is  s−1.