High-sensitivity terahertz sensor based on PT phase change

The invention provides a high-sensitivity terahertz sensor based on PT phase change, a PT phase metasurface is adopted, the PT phase metasurface is of a periodic structure composed of PT symmetrical metasurface units, and each metasurface unit is composed of a dielectric substrate, two annular opening resonance rings and a tunable material; the two planes where the two annular split resonant rings are located are perpendicular to each other, one annular split resonant ring is located in the center of the surface of the dielectric substrate, the other annular split resonant ring is located in the dielectric substrate, and the tunable material is located at the notch of the outer annular split resonant ring. A phase curve of PT phase metasurface cross polarization caused by external excitation change presents significant jump at an EP point, and high-sensitivity sensing of external excitation is realized by using the nonlinear phase jump. Compared with a 2D structure, the anti-Hermite coupling is effectively av