Lasers are only as good as their accuracy which is measured by linewidth. The linewidth is the measurement of the optical spectrum covered by a laser, ideally, we would have achieved a laser with one specific wavelength which would consist of photons being shot at a single frequency, but that hasn’t been possible yet. Scientists have come up with the next best thing, though, and it’s now the sharpest laser in history.
Scientists from the National Metrology Institute of Germany have created a laser with a linewidth of 10 milihertz or 0.01 hertz. This makes it the sharpest laser in history. They say that one of its applications include more accurately measuring th atom’s frequency in an optical clock to maintain our standard of time.
They weren’t able to achieve this overnight, the scientists have actually been working on this for more than ten years. They were able to achieve this with the help of a Fabry-Pérot silicon resonator, it’s a device that’s used to control light wavelength through two fixed mirrors that are placed opposite each other and fixed inside a double cone.
After adjusting all of the variables, the scientists were able to achieve a lser with light waves that oscillate nearly 200 trillion times per second. They’re stable for 11 seconds before they fall out of sync. That’s enough time for the laser beam to hit the Moon and back five times.
The new laser is being used to improve the quality of the clock and measure ultracold atoms with more accuracy. They will eventually be used for other purposes as well.