Tunable terahertz filter using PDLC fishnet metamaterial

摘要

A numerical and experimental study of a tunable single-layered tunable fishnet metamaterials (TFMM) infiltrated with polymer dispersed liquid crystal (PDLC) in THz range is reported. The retrieving procedure of refractive index takes anti-resonance phenomenon into account and is verified by the assumption in effective medium theory. An encapsulating technique that covers PDLC with a 1.5μm polyimide layer (skin layer) was applied to prevent volatile liquid crystal from escaping the PDLC and enable the deposition of metal layer while minimizing the Fabry-Perot effect of the skin layer on the TFMM measurements. Concept of tuning TFMM infiltrated with PDLC (PDLC-TFMM) was proven by measuring the frequency shift in the reflection coefficient (0.01THz), with an observed minimum negative refractive index of-15 at 0.55THz.