A new optical atomic clock’s heart is as small as a coffee bean
The timepiece uses light that ‘beats’ trillions of times per second
PETITE TIMEPIECE The heart of a new miniature atomic clock (shown next to a coffee bean for scale) is a vapor cell (square window on the chip) containing rubidium atoms that “tick” about 385 trillion times per second.
M.T. Hummon/NIST