Most of us take time for granted and presume that seconds are just, well, seconds. For some applications in science and technology, however, being precise down to the millisecond can make a world of difference. For that kind of precision, atomic clocks are the name of the game and the NIST’s in-development clock has a beating hart so small that a coffee bean would stand tall beside it.
Totally not related to explosives, atomic clocks use the signals that atoms give under certain conditions to set the basis for a second. Most atomic clocks today use the natural vibrations of the cesium atom and measure microwave frequencies. This, for example, is the current basis for the international definition of a second.
Microwave frequencies that use oscillators, however, tend to require initial calibration and produce inconsistent frequencies over time, leading to timing errors. Optical atomic clocks, in contrast, can run at higher frequencies and can divide time into smaller units, increasing the clock’s “quality factor”. The problem with these, however, is that they’re often large and complex.
The US National Institute of Standards and Technology or NIST is developing a smaller solution that requires a smaller “heart”. That comes via a “vapor cell on a chip” that measures the activity if rubidium instead of cesium. Rubidium is currently being investigated as a potential replacement for use in future frequency standards.
The NIST’s optical atomic clock requires little room and even less power, just about 275 milliwatts. The institute expects that a clock the size of a handheld device could be manufactured with this new chip. That could make it ideal for use outside of institutions and universities and could be the ticking timers on navigation systems or even as backup clocks on satellites where maintenance is near impossible and power is at a premium.