A research team led by Prof. Sheng Zhangigao of the Hefei Institutes of Physical Science, (HFIPS), of the Chinese Academy of Sciences developed an active and intelligent Terahertz(THz) electronic-optic modulator. The results were published in ACS Applied Materials & Interfaces.

Terahertz technology has been a hot topic in recent years because of its many applications in security, imaging, medicine, and communication. These applications demand high-performance THz devices. Smart and active THz modulators are essential for automatic terahertz imaging and intelligent beam scanning.

The researchers developed an active, smart and efficient THz electro-optic modulator using vanadium dioxide (VO2) films. It can transmit and absorb THz waves, but it can also electrically modify their phase and reflection.

By using an electric-current-induced insulator-to-metal transition in the VO2 film, the researchers achieved near-perfect antireflection (99.9% modulation depth) and 180deg phase switching. A “THz-electroTHz” geometry feedback loop was used to achieve smart electro-optic THz control in the VO2 structure.

No matter the environment or initial conditions, the desired THz amplitude can be achieved precisely.

The proposed electro-optic THz Modulation Method, which uses strongly correlated electron material has opened up possibilities for the realization THz smart devices.