Fabrication Tolerance Sensitivity in Large-Area Mid- Infrared Metamaterial Absorbers

Metamaterial absorbers are photonic structures composed of an array of sub-wavelength metallic patterns. Results in literature are usually based on structures of nominal dimensions, despite the significant effect of fabrication tolerances on performance. This research aims to identify the main sources of uncertainty and to investigate their effect, notably that of an irregular surface quality (i.e., roughness) of the thin metallic layer and the lithography related variations in size and shape. The effect of the shape and positioning of the resonance peak was investigated and validated using mid-infrared metamaterial absorbers. This sensitivity analysis is essential to the batch fabrication of metamaterial absorbers for MEMS applications.