Interplay of surface resonances in one-dimensional plasmonic magnetophotonic crystal slabs

Responses from one-dimensional magnetophotonic crystals terminated by gold layers have been studied experimentally. Such a plasmonic magnetophotonic crystal slab supported an optical resonance (optical Tamm state) originating from the periodicity of the magnetophotonic crystal and a surface plasmon resonance on a gold film's interface. Parameters of the slab and experimental conditions were chosen such that the optical Tamm state and the surface plasmon resonance were excited simultaneously and overlapped in a selected spectral range. Significant alteration of the magneto-optical response together with the change of its sign was observed when tuning the overlap between the resonances.

Figure 1

Sketch of the experimental geometry for OTS and SPR excitation.

Figure 2

(a) Transmissivity of (SiO${}_2$/Bi:YIG)${}^5$ and (SiO${}_2$/Bi:YIG)${}^5$/Au multilayers at normal incidence are shown by gray and black lines, respectively; an optical Tamm state of λ = 750 nm appears within a photonic band denoted by dashed lines. (b) Spectra of the Kerr rotation for the same multilayers as in plot (a); spectra were measured at an angle of incidence of 7° for $p$-polarized light.

Figure 3

(a) Reflection spectra of a Bi:YIG/Au bilayer for internal, in-prism angles of incidence: α = 44.34° (line 1), 45° (line 2), and 45.66° (line 3). (b) Kerr rotation spectra for the same α as in plot (a); line 4 is a reference spectrum of the single Bi:YIG layer at α = 45°. The inset illustrates matching conditions for simultaneous excitation of OTS and SPR in the Kretschmann geometry.

Figure 4

(a) Reflection spectra of the (SiO${}_2$/Bi:YIG)${}^5$/Au multilayer—the plasmonic MPhC slab—for internal, in-prism angles of incidence α = 43°–45.7°. (b) Kerr rotation spectra for same α as in plot (a).

Figure 5

(a) Change of reflection and (b) Kerr rotation spectra of the (SiO${}_2$/Bi:YIG)${}^5$/Au multilayer for α = 45° when overlapping (ON state) and detuning (OFF state) OTS and SPR. The background media adjoined to the Au film were air (black line and squares) and water (gray line and open circles).