This Is the Purest Beam of Light in the World

[Judi Lynn]

By Rafi Letzter, Live Science Staff Writer | February 3, 2019 08:00am ET

- click for image -

https://img.purch.com/h/1400/aHR0cDovL3d3dy5zcGFjZS5jb20vaW1hZ2VzL2kvMDAwLzA4Mi82OTgvb3JpZ2luYWwvNWEzMTQ2NDQ4Mzc1Yy5qcGc=

A team of scientists at the Massachusetts Institute of Technology (MIT) has made the purest laser in the world.

The device, built to be portable enough for use in space, produces a beam of laser light that changes less over time than any other laser ever created. Under normal circumstances, temperature changes and other environmental factors cause laser beams to wiggle between wavelengths. Researchers call that wiggle "linewidth" and measure it in hertz, or cycles per second. Other high-end lasers typically achieve linewidths between 1,000 and 10,000 hertz. This laser has a linewidth of just 20 hertz.

To achieve that extreme purity, the researchers used 6.6 feet (2 meters) of optical fibers that were already known to produce laser light with very low linewidth. And then they improved the linewidth even more by having the laser constantly check its current wavelength against its past wavelength and correct any errors that cropped up. [6 Cool Underground Science Labs]

This is a big deal, the researchers said, because high linewidth is one of the sources of error in precision devices that rely on beams of laser light. An atomic clock or a gravitational-wave detector with a high-linewidth laser can't produce as good a signal as a low-linewidth version, muddling the data the device produces.

More:
https://www.space.com/43210-purest-laser.html

[CentralMass]

1. Thank you for posting another great article.

[Judi Lynn]

2. Thank you, CentralMass. n/t

[lastlib]

3. You always post fascinating stuff that gets my mental gears turnining!

This is another in that great line! Thanks bunches!

[Judi Lynn]

4. They are overwhelming to me when I stumble across them, always so far beyond my understanding.

So much to see, in only one life!

Thank you, lastlib.

[populistdriven]

6. Old method was already very accurate, .000000003% error

Visible is 450,000,000,000,000 to 750,000,000,000,000 hertz

1,000 to 10,000 hertz error is 1 to 10 out of half a trillion. In terms of just the range of the visible spectrum from red to violet it's .000000003% error, with the new method, accuracy improves 50 to 500 times.

This should improve measurements of sea level changes and help with quake forecasting, prediction of volcanic eruptions, and remote acoustic listening

[NBachers]

5. I like paying attention to what the smart people are doing.

[Still In Wisconsin]

7. Physics is so effin' cool.

This is all kinds of awesome.