Interferometers that produce clearer signal by getting rid of light

An interferometer that JPL has sent into space. (credit: JPL)

A lot of what I write is about measurement, not because I'm in love with calipers, but because the cutting edge of physics is at the limit of what we can measure. That means that when you want to think about what to do next, you need to consider how a measurement can be made more sensitive.

Many people, including some scientists, don't realize that you can learn a lot about the world simply by developing new or better instruments. Today, I've decided that the measurement you all need to know about is interferometry. Why? Because interferometers are the fezzes (fezzes are cool) of the physics world. And now, a group of international researchers has come up with a way to make interferometers even more sensitive.

To understand why this is significant, you need to understand why I'm not kidding about interferometry being cool. In the past, an interferometer at a Laser Interferometer Gravitational-Wave Observatory (LIGO) was used to detect gravitational waves. The experimenters at LIGO worked hard to gain control over every aspect of the experiment (except for the gravitational waves—they had no control over them). That included exquisite control over the light source used. In the end, their results involved measuring physical movements that were less than the diameter of a proton. Surely, very few measurement problems would require an even more sensitive interferometer.

Read 19 remaining paragraphs | Comments