Figure 3.

(a) Numerically simulated spatial distribution (x,z) inside the YIG:Co layer at the SPP resonance (λ = 1270 nm). The yellow bars indicate the Au grating. (b, c) Depth profiles (z,λ) integrated across the x-dimension. The dashed lines indicate three λ values that are shown in (c) in detail; B (λ = 1270 nm) corresponds to the resonant SPP excitation. (d) Calculated effective decay depth l_eff of the photomagnetic excitation away from the Au/YIG:Co interface. The top dashed line at 7.5 μm indicates the total thickness of the YIG:Co layer. The bottom dashed line at 300 nm shows the shortest effective depth obtained at the resonance. (e) (top) Calculated reflectivity spectra, before (R) and after (R_c) taking into account the spectral broadening due to the finite laser pulse duration. Full dots: experimental Au/YIG:Co reflectivity. The shaded area illustrates the measured laser spectrum at around λ = 1270 nm. (bottom) Specific efficiency of the photomagnetic excitation for the bare garnet (open dots) and Au:YIG/Co (full dots). The solid red line is the result of the numerical simulations.