Methodology of Designing a Bidirectional Metamaterial Absorber

Most of the existing metamaterial absorber's design exhibits single side absorption due to the presence of metallic reflector at the bottom. A greater challenge is to design a bidirectional metamaterial absorber that provides absorption irrespective of the direction of incidence. In this work we have demonstrated the design methodology of a bidirectional metamaterial absorber by presenting an elaborative study on the structure's evolution. The bidirectional absorber operating in the mid-infrared frequency region exhibits a high absorption (>0.95) while maintaining a low transmission (< 0.15) when incident from either direction (top or bottom). The paper reveals a unique design method that can help to minimize the transmission from such structures and thus can pave the way to design a low transmissive and highly absorptive bidirectional absorber. The methodology presented in this paper might be relevant for the researchers working on various bidirectional and multifunctional optoelectronic devices.