Metasurface-based terahertz functional multiplexing device for amplitude modulation and angle sensing

Terahertz devices play an important role in the development of terahertz technology. Existing terahertz devices have the problems of single function and low integration. Based on terahertz metasurface, a functional multiplexing device was proposed which can realized amplitude modulation and angle sensing simultaneously. The device is composed of a U-shaped metal ring array on the top layer and a sapphire substrate, which is simple in structure and easy to use. The phase difference is introduced by oblique incidence and asymmetric structure, and the Fano resonance is enhanced to improve the device performance. Under the oblique incidence condition, the modulation depth of transmission amplitude can reach 79.3%, the frequency difference between the left and right resonant peaks can reach 92.7 GHz, and the sensitivity of angle sensing is 0.989 5 GHz/(°). The perfomances of amplitude modulation and angle sensing are excellent. The new functional multiplexing device is beneficial to the integration of terahertz devices and provides a new way for the practical application of metasurfaces in modulator and sensor fields.