  A simple metamaterial absorber suitable for fabrication over large areas
associated with a Fano like resonance is proposed. The proposed designed of the
metamaterial absorber consists of photoresist disk arrays on a silicon
substrate followed by the deposition of a tri layer of Au, ZnS and Au on the
top of the structure. Due to the tri layer, there is a formation of a cavity
between the substrate and gold layer on the top of photoresist disk and a
waveguide in the ZnS layer in between the gold layers on the substrate and the
ZnS layer itself. The Fano like resonance arises due to the interference of the
cavity mode and the guided-mode resonance as well as the Woods anomaly. The
cavity mode resonance works as continuum mode whereas the guided mode resonance
and Woods anomaly work as discrete modes. The spectral position of the
resonance can be tuned by just controlling the thickness of the tri layer
instead of the structural size and shape modification of the micro and
nano-structures as usually done in conventional metamaterial absorbers. This
design can be easily scaled for fabrication over large areas as it separates
the structuring and deposition processes and makes them sequential thereby
avoiding expensive and complex lift off or etching processes which are usually
required for conventional metamaterial processing.
