A research group at the Hefei Institutes of Physical Science (HFIPS) of the Chinese Academy of Sciences (CAS) recently investigated an active and smart Terahertz electro-optic modulator and published the results of their efforts in ACS Applied Materials & Interfaces.
Terahertz (THz) technology has promising applications in imaging, communication, medicine, and security. These applications require high-performance THz devices. Among them, active and smart THz modulators are necessary for THz beam scanning, automatic THz imaging, and other smart applications.
The researchers proposed an active and smart THz electro-optic modulator based on VO2 film. It has several advantages. In addition to transmission and absorption, it could electrically modulate the reflection and phase of THz waves.
Using an electric current induced IMT in VO2 film, they achieved near-perfect antireflection (99.9% modulation depth) and 180o phase switching. Based on a feedback loop of “THz-electro-THz” geometry, they also realized smart electro-optic THz control in the VO2 structure.
They could achieve the THz amplitude accurately no matter the initial condition and how the external environment changed. The research opens up avenues for the realization of THz smart devices.