Optical analysis of aligned Ni nanowire arrays with different degree of oxidation for terahertz polarizer application

The optical properties of aligned nickel nanowire arrays (NiNWAs) with different degrees of oxidation for terahertz (THz) polarizer applications have been investigated by using THz time-domain spectroscopy. In frequency-domain spectra, the full width at half maxima of transmitted peaks was broadened and the peak positions have a blue shift with increasing oxidation levels, besides the enhancement in peak intensity. It is indicated that the oxidation of Ni nanowires (NWs) has a significant influence on the interaction between Ni NWs and THz wave. The transmittance of the aligned NiNWAs increases with annealing temperature increasing. Conversely, the degree of polarization and extinction ratio (ER) decreases. A corresponding relationship between the change of ER and degree of oxidation is summarized by means of thermogravimetric analysis. The change of ER for the annealing sample with the degree of oxidation of 0.507% is 27.32%, which induced the polarization properties of aligned NiNWAs to be sensitive to the oxidation of Ni NWs. These findings can provide new positive features in the development of future polarization-based device applications for THz electronics and photonics. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

The optical properties of aligned nickel nanowire arrays with different degrees of oxidation were studied for terahertz polarizer applications using THz time-domain spectroscopy. It was found that increasing oxidation levels broadened the transmitted peaks in the frequency-domain spectra and caused a blue shift in peak positions, while also enhancing peak intensity. The transmittance of the arrays increased with annealing temperature, but the degree of polarization and extinction ratio decreased. The study also revealed a correlation between the degree of oxidation and the change in extinction ratio.