Chip-scale atomic clock

<p>A chip scale atomic clock (CSAC) is a compact, low-power atomic clock fabricated using techniques of <a href="/facts/Microelectromechanical_systems/TkhEzDpm">microelectromechanical systems</a> (MEMS) and incorporating a low-power semiconductor laser as the light source. The first CSAC physics package was demonstrated at the National Institute of Standards and Technology (<a href="/facts/National_Institute_of_Standards_and_Technology/gr9Fnh85">NIST</a>) in 2003, based on an invention made in 2001.  The work was funded by the <a href="/facts/US_Department_of_Defense/dWAvf7e3">US Department of Defense</a>'s <a href="/facts/Defense_Advanced_Research_Projects_Agency/Uf9sarhT">Defense Advanced Research Projects Agency</a> (DARPA) with the goal of developing a <a href="/facts/Microchip/fjn6vg7C">microchip</a>-sized <a href="/facts/Atomic_clock/MF8nsXDR">atomic clock</a> for use in portable equipment.  In military equipment it is expected to provide improved location and <a href="/facts/Battlespace/vaKgGQBe">battlespace</a> <a href="/facts/Situational_awareness/0EMpWgTa">situational awareness</a> for dismounted <a href="/facts/Soldier/f3tcRU9C">soldiers</a> when the <a href="/facts/Global_positioning_system/DKVLnzF3">global positioning system</a> is not available, but many civilian applications are also envisioned. Commercial manufacturing of these atomic clocks began in 2011.  The CSAC, the world's smallest atomic clock, is 4 x 3.5 x 1 cm (1.5 x 1.4 x 0.4 inches) in size, weighs 35 grams, consumes only 115 mW of power, and can keep time to within 100 microseconds per day after several years of operation.
A more stable design based on the vibration of <a href="/facts/Rubidium/KDHSe2HM">rubidium</a> atoms was demonstrated by NIST in 2019.
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Chip-scale atomic clock open-in-new

Chip-scale atomic clock