Fig. 1. Scheme of the Au/ITO-NA fabrication process.

Fig. 2. (a) Digital photograph and (b) FESEM images of the Au/ITO-NA; (c) AFM topography of the sample and 2D longitudinal profile along the blue dashed line; high magnification SEM image of the (d) front and (e) back part of the Au/ITO-NA; (f) EDS results of the sample (inset: EDS 2D mapping of different elements in the Au/ITO-NA).

Fig. 3. SEM images of (a) ITO-15, (b) ITO-20, (c) Au-20-NPA (inset: Au-20-NPs), (d) Au-10/ITO-20, (e) Au/ITO-NA, and (f) Au-30/ITO-20; formation mechanism schemes of (g) Au-10/ITO-20, (h) Au/ITO-NA, and (i) Au-30/ITO-20.

Fig. 4. Optical extinction spectra of all the prepared samples.

Fig. 5. (a) Extinction (E), absorption (A), and scattering (S) of the Au/ITO-NA; (b) comparison of the absolute absorbance of Au/ITO-NA and Au-20-NPA.

Fig. 6. Schematic diagram of the fs-I-scan system used for the nonlinear transmission/absorption experiment.

Fig. 7. TPA saturation effect of the Au/ITO-NA under the excitation of 340 fs, 1030 nm, and 1 kHz laser pulses.

Fig. 8. TPA measurement results with repeated scan at the same point on the sample.