Soft Ferrite Bi-layer Design of Frequency Selective Micro Cavity

The designs for Frequency Selective Micro Cavity (FSMC) structures in the terahertz band have been proposed, based on ferrite composite layers. A high-value complexpermittivity Ni0.5Co0.2Zn0.3Fe2O4 base layer has been previously reported and demonstrates low transmittance at 1 THz and above. The scope entails design of Anti-Reflective Coatings (ARC) for broad-band (0.5-2.5 THz) cavity absorbance of 90% and higher. The reported deliverables are as follows - (i) development of thick film coatings with tunable refractive index based on SU8 and micro-machined ferrite grains, (ii) analytical studies to determine ARC properties (single and bi-layer) for optimal performance, and (iii) multi-physics simulations. The results reported from (ii) and (iii) are well matched. Ongoing work involves setup development for THz reflectance measurements to help validate cavity performance and explore cavity applications.