Figure 4.

Dependence of plasmon amplitude on the excitation current parameters. The solid curves are the results of analytical calculations, the dotted ones are the results of numerical calculations. (a) Dependence of the SPP amplitude on the length of the sinusoidal current when the SPP parameters (${\lambda }_{\mathrm{SPP}}=0.783$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=92$ $\mathsf{\mu }$m, $\lambda =0.8$ $\mathsf{\mu }$m) remain unchanged and the current modulation period $\Lambda$ varies. (b) The dependence of the SPP amplitude (${\lambda }_{\mathrm{SPP}}=0.783$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=92$ $\mathsf{\mu }$m, $\lambda =0.8$ $\mathsf{\mu }$m) on the current modulation period, with variation in the current zone’s length. (c) Dependence of the SPP resonance amplitude on the length of the sinusoidal surface current for different grating periods $\Lambda$. A vacuum wavelength $\lambda$ is chosen to provide the resonance condition ${\lambda }_{\mathrm{SPP}}=\Lambda$. Curve 1: $\Lambda =568$ nm ($\lambda =0.6$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=9.6$ $\mathsf{\mu }$m). Curve 2: $\Lambda =687$ nm ($\lambda =0.7$$\mathsf{\mu }$m, $l_{\mathrm{SPP}}=52$ $\mathsf{\mu }$m). Curve 3: $\Lambda =783$ nm ($\lambda =0.8$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=92$ $\mathsf{\mu }$m). Curve 4: $\Lambda =886$ nm ($\lambda =0.9$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=147$ $\mathsf{\mu }$m). Curve 5: $\Lambda =988$ nm ($\lambda =1.0$ $\mathsf{\mu }$m, $l_{\mathrm{SPP}}=183$ $\mathsf{\mu }$m).