We theoretically propose and investigate a light-controllable narrow-band terahertz (THz) filter and a dual-wavelength filter employing a square lattice photonic crystal with point and line defects. The point defects filled the photoresponsive liquid crystal. The change of the refractive index of the liquid crystal mixture material caused by the linearly polarized ultraviolet (UV) light and visible light results in a shift of the resonant wavelength of the cavity in the filter. We calculate transmittance spectra for the proposed THz wave filters, which have a full width at half maximum of 10 GHz and a transmittance of 95% at the resonant frequencies. By changing the polarized directions of UV and visible light, the performance characteristics of the filters can be adjusted.
Refractive index sensing is attracting extensive attention in biochemical sensing using terahertz technology. Various structures with strong confinements have been used to design sensors for improving the interaction between the terahertz wave field and the analytes, such as photonic crystals, nanowires, plasmonic structures, and metamaterials. Terahertz wave sensors based on two-dimensional photonic crystal have been used in various areas ranging from disease diagnostics to environmental pollution detection. For improving the performance of terahertz sensor, a sensing scheme based on high-density polyethylene sunflower-typecircular photonic crystal structure is proposed. The designed sensor contains two symmetrical sample cells surrounding a cavity in a circular photonic crystal. The transmission properties of the terahertz wave sensor are analyzed based on COMSOL Multiphysics when the central sample cells are filled with analyte with different refractive indices. The sensor characteristics depending on the structure parameters are analyzed. The choice of these parameters is discussed. Finally, a sensitivity of 10.4 μm/RIU, <i>Q</i>-factor of 62.21, and figure-of-merit of 1.46 are realized. The results in this work are expected to be able to extend the circular photonic crystal-based sensor to terahertz wave region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.