{"id":65,"date":"2023-12-12T16:00:39","date_gmt":"2023-12-12T15:00:39","guid":{"rendered":"https:\/\/physicsworld.com\/?p=111785"},"modified":"2023-12-12T16:00:39","modified_gmt":"2023-12-12T15:00:39","slug":"portable-optical-atomic-clock-makes-its-commercial-debut","status":"publish","type":"post","link":"https:\/\/hadamard.com\/c\/portable-optical-atomic-clock-makes-its-commercial-debut\/","title":{"rendered":"Portable optical atomic clock makes its commercial debut"},"content":{"rendered":"

Atoms are the world\u2019s most precise timekeepers \u2013 so much so that the second is defined as exactly 9 192 631 770 ticks of a caesium-based atomic clock. Commercially-available versions of these atomically precise clocks underpin GPS, navigation, data transfer and financial markets, and they run at microwave frequencies, or billions of tick-tocks per second. After a day, their timekeeping is out by less than ten nanoseconds.<\/p>\n

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As good as this is, though, the next generation of atomic clocks is even more precise. These lab-based constructions run at optical frequencies, meaning they tick tens of trillions of times per second. The best of them can remain precise to 10 femtoseconds (10-15<\/sup> s) after a day, or within a second after 50 billion years. And soon, for the first time, you\u2019ll be able to buy one of your very own: Vector Atomic, a start-up based in California, US, has put the first portable optical clock on the market<\/a>.<\/p>\n

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\u201cToday the only clocks you can buy are microwave clocks,\u201d says Jonathan Hoffman<\/a>, a programme manager at the US Defense Advanced Research Projects Agency (DARPA), which funded the work. \u201cIf you go to the optical transition, there\u2019s a giant gain in precision, accuracy and performance, but it also typically comes with incredible complexity at the same time. Finding a happy compromise is the real battle.\u201d<\/p>\n

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Finding the right atoms<\/h3>\n

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The main difference between optical clocks and their microwave predecessors is lasers. To build the most precise clocks possible, scientists use the atoms that offer the narrowest atomic transitions \u2013 usually strontium or ytterbium \u2013 and design their laser systems around those atoms\u2019 particular requirements. The atoms are kept in vacuum chambers, and different lasers are used to cool and trap them, while other lasers block undesirable transitions or interrogate the desired one used in the clock. All these lasers, up to a dozen total, need to be stabilized to precise frequencies, and maintaining them requires constant supervision.<\/p>\n

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To build a less precise, but more robust and portable, version of an optical clock, Vector Atomic CEO and co-founder Jamil Abo-Shaeer<\/a> had to take a different approach. \u201cInstead of designing the system around the atom, we designed the system around the lasers,\u201d he says.<\/p>\n

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\"Photo<\/a>