Fig. 2
Strong coupling between excitons and SPPs in a WS2-clad Ag MNW. a Solutions in the complex-momentum (complex-k) plane by feeding real-valued ω. Left: dispersion relation in terms of ħω vs. Re(k) featuring back-bending. Right: trajectories of ħω and Im(k). Red squared, yellow dashed, and black dashed lines: PEPP, SPP, and excitons. b Solutions in the complex frequency (complex-ω) plane by feeding real-valued k. Left: dispersion relation in terms of ħRe(ω) versus k featuring anti-crossing. Right: trajectories of ħRe(ω) and ħIm(ω). The numerically obtained result for the PEPP is denoted by blue (upper branch, UP) and red dots (lower branch, LP), showing excellent agreement to the result obtained from the coupled-oscillator model (COM, blue and red lines) with a Rabi splitting energy ~ 85.7 meV (green arrow). Yellow and black dashed lines: SPP and excitons. c Fractions of excitons (black lines) and the SPP (yellow lines) in the PEPP. Left: upper branch. Right: lower branch. The diameter for Ag MNW here is 50 nm