Fig. 4. Experimental realization of the underwater metamaterial absorber with water pool measurement.

(A) Fabricated composite rods, placed on the stepped stainless-steel base. (B) One sample unit and the waterproof effect on the top surface, with the adoption of the soft glue. Water is shown to form a droplet shape because of the hydrophobic effect of the waterproof soft glue. (C) Front view and back view of the assembled sample, comprising nine units. (D) Schematic of the water pool measurement configuration. (E) Measured data with the transmittance T, the reflectance R, and the absorption A = 1 − T − R. The results retrieved from simulation are also presented by dashed lines, for comparison. Here, the simulations have taken into account the stainless-steel base.