Fig. 1. (a) Scheme of the reconfigurable phase-change HMM absorber, where the structure is composed of Au–GST225 stacked layers. Both the GST225 and Au films have an identical thickness of 40 nm. The whole HMM absorber sits on a silica substrate. (b) FIB image of the cross-section of the HMM absorber. (c) Real parts of the ε_‖ and ε_⊥ of the HMM absorber extracted from VASE as transiting the GST225 state from amorphous (top panel) to crystalline (bottom panel). (d) The VASE measured (top panel) and FDTD simulated (bottom panel) A(ω) of the HMM absorber for the amorphous and crystalline states.