An international team of physicists has developed a new method for determining the precise color of laser light using an image that rotates as the laser’s frequency shifts.

The finding could offer a new way to ensure that lasers are ‘locked’ to the frequencies needed by technologies that rely on them, from GPS positioning to quantum sensors. It could also spur developments in spectroscopy, magnetometry and quantum communications.

In a new paper published in the journal Optica, the University of Glasgow-led team describes how it devised a way to determine the frequency of a laser beam in a single snapshot.