Selection of metals for the optimal performance of metamaterial based hollow core fibers for terahertz applications

Abstract

Terahertz (THz) radiation has recently gained much attention in diverse fields ranging from short-range wireless communication to biomedical applications. In general, THz radiation is much difficult to transmit through conventional waveguides due to experiencing higher transmission losses. Many waveguide-based technologies have been proposed in recent decades; among these, hollow-core fiber (HCF) is one of the best options due to the lower material absorption and dispersion. Recently, metamaterial-based HCF shows great promise to transmit THz radiation due to its unique and tunable optical properties. This work focuses on the effect of different metal wires (e.g. indium, silver, and gold) on the confinement loss (CL) of metamaterial-based HCFs. Numerical simulations are carried out from 0.24 to 1.5 THz with a 1 mm diameter core and metamaterial cladding made of subwavelength size metal wires embedded in Zeonex. The impact of the diameter, position, and number of metal wires have been thoroughly investigated. It is observed that the effect of increasing the wire diameter and the number of wires around the core have similar effects as the fraction of metal increases in the cladding layer for both the cases. However, there is an optimal position of wires embedded in a dielectric, where the loss is found to be the lowest. Thus, the metamaterial-based HCF design needs to be optimized to achieve the lowest loss at a specific spectral range. This analysis could help to select metal wires with associated parameters for designing low-loss metamaterial-based HCF in the THz region.