Active and Smart Terahertz Electro-Optic Modulator Based on VO2 Structure

Modulating terahertz (THz) waves actively and smartly through an external field is highly desired in the development of THz spectroscopic devices. Here, we demonstrate an active and smart electro-optic THz modulator based on a strongly correlated electron oxide vanadium dioxide (VO2). With milliampere current excitation on the VO2 thin film, the transmission, reflection, absorption, and phase of THz waves can be modulated efficiently. In particular, the antireflection condition can be actively achieved and the modulation depth reaches 99.9%, accompanied by a 180 degrees phase switching. Repeated and current scanning experiments confirm the high stability and multibit modulation of this electro-optic modulation. Most strikingly, by utilizing a feedback loop of THz-electro-THz geometry, a smart electro-optic THz control is realized. For instance, the antireflection condition can be stabilized precisely no matter what the initial condition is and how the external environment changes. The proposed electro-optic THz modulation method, taking advantage of strongly correlated electron material, opens up avenues for the realization of THz smart devices.

Automated summary

This article demonstrates an active and smart electro-optic terahertz modulator based on strongly correlated electron oxide vanadium dioxide. By applying an external electric field, the transmission, reflection, absorption, and phase of terahertz waves can be efficiently modulated, with the ability to stabilize the antireflection condition.