Extended Data Fig. 5: Demonstration of the dominant mode of the THz SPPs.
From: Coherent surface plasmon polariton amplification via free-electron pumping
a, Illustration of \({c}_{01}\) (magenta line) as a function of z at a specific moment. The black dashed line marks the position where \({c}_{01}\) is maximal in the longitudinal cross-section of the electric-field profile (Ey). (b and c–h) Several snapshots of transverse cross-section of the electric-field profile (Ey) transected at the z where \({c}_{01}\) is maximal.
