NIST on a Chip: Realizing SI units with microfabricated alkali vapour cells

We describe several ways in which microfabricated alkali atom vapour cells might potentially be used to accurately realize a variety of SI units, including the second, the meter, the kelvin, the ampere and the volt, in a compact, low-cost “chip-scale” package. Such instruments may allow inexpensive in-situ calibrations at the user’s location or widespread integration of accurate references into instrumentation and systems.