In 2008, a team of UCLA-led scientists proposed a scheme to use a laser to excite the nucleus of thorium atoms to realize extremely accurate, portable clocks. Last year, they realized this longstanding goal by bombarding thorium atoms embedded in specialized fluoride crystals with a laser. Now, they have found a way to dramatically simplify and strengthen the process by replacing the specialized crystals with thorium electroplated onto steel.
They observe, for the first time, that laser excitation of the thorium nucleus in this system leads to a measurable electric current, which can be used to miniaturize the nuclear clock. The advance is needed for smaller, more efficient atomic clocks, which have long been sought to improve navigation, GPS, power grids, and communications. It will also allow for some of the tightest tests ever of fundamental physics.









