Phase‐Changing Vanadium Oxides for Electromagnetic Radiation Management

Vanadium oxides and their polymorphs are transforming electromagnetic radiation security in communications and infrastructure. This arises from their broadband response and potential for wavelength attenuation across the ultraviolet, optical, infrared, and radio regions of the electromagnetic spectrum. More specifically, monoclinic vanadium dioxide's sharp, reversible insulator‐to‐metal transition near room temperature enables ultrafast, tuneable switching of conductivity and optical properties, triggered by thermal, optical, or electrical controls. Chalcogenide phase‐change materials require high crystallisation temperatures and nanosecond switching times, whereas VO 2 's volatile Mott transition operates near ambient conditions with femtosecond response and cycling stability exceeding 100 million cycles. This dynamic modulation supports real‐time absorption, shielding, and beam steering across terahertz, infrared, and radiofrequency domains, with demonstrated absorption rates tuneable from 2% to 100% and bandwidths up to 6.35 THz. VO 2 metasurfaces offer polarisation insensitivity and multifunctionality, protecting against jamming, interception, and signal leakage. Advances in large‐area synthesis, nanostructuring, and durability have enabled both highly sensitive sensors and long‐lived smart coatings. These findings position vanadium oxides as transformative materials for physical‐layer electromagnetic security in wireless communications, infrastructure protection, and smart sensing systems.