To identify the origin of optical losses, we have performed FDTD simulations for different adhesion Cr and Ti films as well as for different Au thicknesses. The results are shown in Fig. and Fig. . When there was no adhesion layer (Fig. ), a film of 10 nm of gold kept transparency above 80% at visible wavelengths. However when the adhesion layer of 5 nm Cr or Ti has added between metal and dielectric layer, the transmittance drastically decreased to less than 40%. The effect of Au ground plate thickness has simulated and is shown in Fig. for all range of MIM metasurfaces with different nanodisk diameters. Interestingly, with an increasing thickness of Au, the transmission was still kept above 40%. It was promising that even at 30 nm Au film, ≈ 80%.