Controlled absorption/reflection bi-directional tuning GaAs terahertz wave device

Terahertz metamaterials exhibit significant potential for applications in electromagnetic ultrafast response, wavefront modulation, and electromagnetic wave transmission. However, the transmission properties of these metamaterials remain fixed once the structure and materials of the device are established, which severely limits their modulation capability and operational range. In this study, a terahertz wave device that enables absorption/reflection bi-directional modulation was designed based on the property that the conductivity of GaAs can be modulated by pumping light. The results indicate that when the GaAs conductivity is 100 S/m, the absorption of the terahertz device within the 1.278-3.087 THz band exceeds 90%, with an absorption bandwidth of 1.809 THz, and RCS reduction can be achieved. As the pump optical power increases, the reflection of the terahertz device approaches 100% across the 0-3.5 THz band when the GaAs conductivity reaches 1×10⁶ <i>S</i>/<i>m</i>. Furthermore, simulation results demonstrate that the device is insensitive to variations in polarization and incidence angles. The device is anticipated to have further applications in optical switching and electromagnetic stealth.