The submillimeter wave, or terahertz, part of the electromagnetic spectrum falls between the frequencies of 0.3 and 3 terahertz, between microwaves and infrared light. Historically, device physics has prevented traditional solid state electronics (microchips) from operating at the terahertz scale. Unlocking this band’s potential may benefit military applications such as data rate communications, improved radar and unique methods of spectroscopy-imaging techniques that provide better tools for scientific research. However, access to these applications is limited due to physics.

Researchers under the Defense Advanced Research Projects Agency’s (DARPA) Terahertz Electronics (THz) programme have designed and demonstrated a 0.85 Terahertz power amplifier using a micromachined vacuum tube—a world’s first. The achievement comes from DARPA-funded researchers at Northrop Grumman Electronic Systems, who built the 1 centimetre-wide travelling wave vacuum tube. The vacuum tube power amplifier is only one achievement of the broader THz programme, which seeks to develop a variety of breakthrough component and integration technologies necessary to one day build complex THz circuits for communications and sensing.

“Further research and development in this field will help unlock applications for our military in this historically difficult to access part of the spectrum,” said Palmer.