Modeling and simulation of multilayered thin films for terahertz detection

In this article we demonstrate a method based on Transfer Matrix (TMM) that can be used to analyze optical properties of multilayered thin films and planar metamaterials for terahertz (THz) detection. Producing and testing such films require host substrates that can be up to 4 orders of magnitude thicker than the THz-sensitive films. Therefore, the ability to efficiently model, simulate and accurately predict the optical properties of multilayered structures, with significant differences in thickness, is crucial to designing sensors with maximized absorption. This method, which provides an analytical tool, less computationally intensive then finite element modeling, can be used for films composed of any number of layers with arbitrary thicknesses, aspect ratios and arbitrary angles of incidence. Homogeneous or patterned (metamaterials) films can be modeled enabling accurate analysis of positive and negative index materials indistinctly. Reflection, transmission and absorption of metallic/dielectric nanolaminates, metallic thin films and planar metamaterial films are analyzed and compared with experimental measurements and FE simulations. Results show good agreement for a wide range of structures, materials and frequencies and indicate that the method has a great potential for design and optimization of sophisticated multilayered structures for THz detection and beyond.