Optical clocks, which use visible light waves to measure time, have become the most accurate and stable clocks in existence, surpassing the 50-year-old cesium standard. These clocks divide the second 100,000 times more finely than microwave clocks, allowing for unprecedented precision in timekeeping.
To create optical clocks, scientists use atoms with resonant frequencies in the optical range, such as aluminum, strontium, and ytterbium. They also employ extremely stable laser light, frequency combs, and optical cavities to measure the atoms’ oscillations with high accuracy.
Two main types of optical clocks exist: trapped-ion clocks and optical lattice clocks. Trapped-ion clocks use single charged atoms trapped in electromagnetic fields, while lattice clocks use thousands of atoms trapped in a laser-created energy landscape.
Despite their complexity and size, portable optical clocks are beginning to be used in real-world applications, such as testing Einstein’s theory of general relativity and providing timekeeping for navigation satellites. The future of optical clocks looks promising, with continued improvements in accuracy and stability.
Source: https://www.nist.gov/atomic-clocks/optical-clocks-future-time
Keywords: Quantum Sensing and Metrology
