Fig. 1. Diagram of two disk cavities with apertures linked to a plasmonic waveguide system with frequency mistuning between the two disk cavities. Disk cavity 1 is overlaid by the optical Kerr nonlinear material single-layer graphene.

Fig. 2. Diagram of a simple system model to achieve the PIT effect.

Fig. 3. Relationship between the variation in the resonant wavelength of a disk cavity and the pump light intensity.

Fig. 4. Transmitted spectra (a1)–(e1), transmitted phase shift responses and group indices (a2)–(e2) under various pump light intensities when disk cavity 1 is overlaid by a graphene layer with a thickness of 0.5 nm. The black dots stand for the group indices of the PIT peaks with values of 53.2, 38.8, 27.5, 19.8, and 15.1.

Fig. 5. Relationship between the group velocity and the pump light intensity under frequency mistuning for tuning slow light.

Fig. 6. Diagram of two disk cavities with apertures linked to a plasmonic waveguide system and with the propagating phase detuned between the two disk cavities. The plasmonic waveguide between the two cavities is overlaid by the optical Kerr nonlinear material single-layer graphene.

Fig. 7. Real part of the effective refractive exponent and phase shift satisfying the dispersion formula in a plasmonic waveguide with w = 50 nm. The black dot indicates the value of π that meets the dispersion formula at λ = 789 nm.

Fig. 8. Transmitted spectra (a1)-(e1), transmitted phase shift responses and group indices (a2)-(e2) at diverse pump light intensities when the plasmonic waveguide between the two disk cavities is covered by a 0.5 nm thick graphene layer. The green dots stand for the group index of the transparent wavelength at 789 nm with values of 14.8, 7.9, 2.8, 7.9, and 14.8.

Fig. 9. Distribution of |H_z|² at dip wavelengths of 784 nm (a) and 794 nm (c) and transparent wavelength of 789 nm (b) under a pump light intensity of 11.76 MW/cm². The relevant transmitted spectrum is shown in Fig. 8(e1).

Fig. 10. Relationship between the group velocity and the pump light intensity under the propagation phase of the plasmonic waveguide slow-light tuning mechanism.