The World's Smallest Atomic Clock

Researchers in the US have developed the world's smallest commercial atomic clock. Known as the SA.45s Chip Size Atomic Clock (CSAC), it could be yours for just $1500. The clock, initially developed for military use, is about the size of a matchbox, weighs about 35 grams and has a power requirement of only 115 mW. Not your everyday timekeeper, the team behind the clock claim that it could have varied and wide-ranging applications, from disabling bombs to searching for oil.

Atomic clocks use a specific electronic transition frequency of an atom as a frequency standard, with the "ticks" being the oscillations between two energy states in an atom. Generally, a feedback loop is used to lock the frequency of a light source to that of the transition, thus creating a stable frequency standard.

This latest clock has been jointly developed at Symmetricom, Draper Laboratory and Sandia National Laboratories in the US. The clock comprises a highly compact "physics package" that contains the caesium atoms used and sits on a circuit board within a tiny box. The caesium atoms are held within a resonance cell and are heated to a vapour state by plates situated at the top and bottom of the package.…

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