This results in radiative coupling of J0 transverse modes in the gap (although additional nonradiative J1 modes are present).
The coupling between the plasmonic and waveguide modes across the gap enables 'capacitor-like' energy storage that allows effective subwavelength transmission in non-metallic regions.
The Neptunes' work was a fanciful synthesis of old modes (Queen, the Gap Band, Stevie Wonder, the Jackson 5, Earth, Wind & Fire) and new technologies, though it is sometimes difficult to tell where one ends and the next begins.
In order to study the propagation of these surface waves (SPs) and formation of plasmonic modes in the gap distance between metals, we use both numerical and analytical methods.
The product across modes increases the gap between the predicted and the actual eigenvalues as shown in Figure 1.
We can also test the idea that the modes below the gap should scale with the square root of the reduced mass taking into account the metal ions (Fig. 4, bottom panel); the displacement patterns of Fig. 3 suggest that this will not be so successful, because both metal and chalcogen atoms are displaced significantly in the below gap modes.
For the modes above the gap, this is the chalcogen mass, and therefore, we replot the calculated phonon frequencies in Fig. 4 (top panel) multiplied by (sqrt {32.065}=5.66) (sulphides) and by (sqrt {78.96}=8.89) (selenide).
The concordance between the models can be appreciated in Fig. 16, in particular for the first nine modes, while the gap becomes noticeable at increasing but less important frequencies.
The designed structure transfers 70.8% of the power carried by the silicon waveguide mode to the plasmonic slot waveguide mode when the gap is 150 nm and the coupling length is 2.14 μm.
Obviously, the field intensity of the symmetric mode in the gap region is stronger than that of the anti-symmetric mode.
