Researchers at MIT and Princeton have built a new laser-powered terahertz spectroscopy system capable of detecting chemicals used in explosives.

Terahertz spectroscopy is the measurement of electromagnetic radiation between the frequencies of microwaves and infrared. Scientists have long realized the radiation’s potential for bomb detection, but traditional terahertz spectroscopy systems are bulky and use lots of power. They also take a long time to analyze sample materials.

The new system uses a computer chip-size quantum cascade laser, and can detect terahertz signatures in just 100 microseconds.

The device produces a laser-powered frequency comb — a spectrum made up of a series of equally spaced frequencies. The variety of frequencies allows the device to create a unique terahertz-absorption profile in just a few measurements.