Starre Julia Vartan

I tackled a tough assignment for SciAm that required me to learn the ins and outs of optical frequency combs and dig deep into my physics knowledge to explain it in plain language. Thanks to the patience of my SciAm editor, I finally got it after a few rounds!

Explaining complexity simply is one of the science writer’s most important jobs and one I take really seriously—I liken it to a puzzle, where you know what the finished piece looks like, and you have the pieces, but you need to figure out how they connect together in a way that makes sense. It’s a challenge but fun (although can be frustrating along the way!). Here’s the finished product:

Astronomers and physicists have long used a laser-based sensor called an “optical frequency comb” to study the material makeup of the cosmos and to make timekeeping more accurate. But the COVID pandemic has pushed this versatile tool from the world of space and physics into health care.

Optical frequency combs are lasers that simultaneously shoot pulses of light at multiple frequencies. Because these superfast pulses are precisely spaced along the light spectrum—from infrared through the visible colors to ultraviolet—they form a series of peaks on a graph of the frequencies that look like the teeth of a comb. This “comb” can be used in a variety of ways. For instance, different types of molecules absorb different colors of light; by detecting which colors of light are absorbed near specific frequencies, the comb can identify specific molecules in an air sample. In a recent study, scientists proved this tool can detect COVID from Breathalyzer-type tests in which subjects simply blow into a tube—potentially paving the way for fast, noninvasive diagnostic tests for a multitude of diseases.

Read the full article on Scientific American here.