Light Clock Promises Finer Time

“Hey, I think your atomic clock needs to be set back a minute or two.” Could statements like this one day become common place? Well according to a report from Technology Review, it could happen sooner than we think.

Based on my limited understanding of how Atomic clocks actually work, they are designed to work with microwaves to calculate time. If this new technology takes off, we will see atomic clocks using optical radiation instead.

Making the most of time requires that time be well defined. And in order to be precise, a definition of time must involve something that happens very quickly.

The current definition of a second is the duration of 9,192,631,770 oscillations of cesium atoms excited by microwaves. Today’s cesium atomic clocks are accurate to within one million billionth of a second, or 1 second in 30 million years.

This is precise enough for a cluster of orbiting satellites to calculate the position of a stationary object to within a millimeter. For moving objects like cars and planes, however, the accuracy is a few meters, which is not enough to allow a global positioning system to, for instance, automatically land a plane.

Researchers from the National Physical Laboratory in England have made a prototype atomic clock that divides time into slices based on optical radiation, or lightwaves, rather than microwave radiation.

Lightwaves are smaller and faster than microwaves, and so divide time into much finer slices, which makes for higher accuracy. Such clocks could eventually improve global positioning systems, make space exploration more accurate, and more accurately test the laws of physics.