Zinc oxide nanorods electronically controlled terahertz modulator

Metal oxides are commonly employed in terahertz (THz) modulator devices operating in the THz frequency band. These metal oxides, which rely on electronic control, exhibit a clear response to THz waves. The modulation of THz waves is achieved by applying an electric field directly onto the surface of ZnO nanorods and their metal dopants. This external electric field has the capability to modulate both the phase and transmittance of the THz wave. The devices based on Au-doped ZnO nanorods demonstrate a significant enhancement in modulation depth due to the incorporation of the localized surface plasmon effect. In the realm of active THz modulation, the velocity of electric modulation is enhanced while the required driving power is reduced. The primary focus of this research article is to present an analysis of the active modulation properties and the underlying principles of ZnO nanorods and their metallic dopants when subjected to an applied electric field. The modulation bandwidth range from 0.1 to 1.0 THz for our devices. The phase modulation of 0.866 rad and the transmittance modulation with the modulation depth of 0.4 was realized.