Scientists develop active and smart terahertz electro-optic modulator

 https://phys.org/news/2022-08-scientists-smart-terahertz-electro-optic-modulator.html

"active and smart THz electro-optic modulator based on VO2 film... near-perfect antireflection (99.9% modulation depth) and 180° phase switching. By utilizing a feedback loop of "THz-electro-THz" geometry, they also realized smart electro-optic THz control in the VO2 structure. The desired THz amplitude could be achieved accurately no matter what the initial condition was and how the external environment changed...  could electrically modulate the reflection and phase of THz waves"