Changes in the ions' vibration rate were measured by bouncing laser light off them.

ECONOMIST: Scientists measure a few yoctonewtons for the first time

That happens because, provided those electrons that have given off light are quickly pumped back to their excited states, the light bouncing around between the mirrors will stimulate the production of yet more light and a powerful, coherent beam will emerge.

ECONOMIST: Optoelectronics

To make them sensitive to the deflection caused by pressure, the researchers carved grooves in the fibres along their length so that the bouncing of the light was less efficient at the point where pressure was applied.

BBC: 'Magic carpet' can detect or even predict a fall

MOLA, which works by bouncing beams of light off the planet's surface, has found mountains twice as high as Everest, a crater ten kilometres deep, and huge valleys carved by more water than scientists believed had ever existed on Mars.

ECONOMIST: Martian chronicles

Once the balls stopped bouncing, the rovers shucked off their shells and emerged into the Martian light.

NEWYORKER: The Martian Chroniclers

The camera works, the team explained, by bouncing lasers off distant objects, and measuring the time it takes for the light to travel back to the detector.

BBC: Long-distance 3D laser camera unveiled by Edinburgh team