Figure 2

Three-dimensional illustration of the proposed switchable metasurface arranged in periodic array. (a) When there is no liquid metal inside the microchannels, incident EM wave travels through the entire thickness and broadband absorption occurs over the frequency range of (f₁ – f₂). (b) With the injection of EGaIn, the microchannels behave as an adaptive ground, and restricts EM wave for further penetration, which causes the shift in the absorption spectrum to (f₃ – f₄). Outside the absorption window, the incident wave is reflected back to the first medium, as indicated by the red and green arrows. Absorption of EM wave is designated by the blue arrows.