A functionality switchable meta-device: from perfect reflection to perfect absorption

Tunable meta-devices trigger immense interest in many applications like biosensing, thermal camouflage, radiative cooling, thermal emitting, infrared imaging, and energy harvesting. This paper presents a polarization-independent broadband tunable absorbing and reflecting meta-device using a phase change material Germanium-Antimony-Tellurium (GST). The proposed design manifests high absorptivity >80% over a broadband range of wavelength spanning the mid-IR regime. Furthermore, by changing the phase of GST material from crystalline to amorphous with the help of external stimuli, the absorbance of the device was reduced to almost zero in the range from 4 μm to 12 μm. To previse the angular constancy of the meta-absorber, the absorptivity was scrutinized under different incidence angles in both transverse magnetic (TM) and transverse electric (TE) polarizations which manifested the robustness of the proposed meta-absorber. As a result, the proposed absorber has tunable broadband absorbance and angular stability, which proclaim great potential in applications such as thermal camouflage, radiation detection, thermal emitter, and stealth technology, etc.