History of Laser Cooling: Part 1

In which I play journalist

I’ve made a few references here to the fact that I’ve been working on a piece about the history of laser cooling. That very quickly exceeded the word count for a single feature, so will run as three parts, the first of which is out now at Physics World: Cold: How physicists learned to manipulate and move particles with laser cooling.

The background for this is that I’m a cold-atom guy by training: I did my Ph.D. with Bill Phillips at NIST in Gaithersburg on collisions between xenon atoms at ultra-low temperatures (millionths of a degree above absolute zero). And I was drawn into the field by its gloriously counterintuitive (to repeat a phrase from the first paragraph of the article) nature: the first time I heard the idea of making a gas cold by simply shining laser light on it, it blew my mind. When I heard that a couple of my undergrad professors were working on a laser cooling experiment, I rushed to sign up for that.

More recently, in writing about atomic clocks for both Breakfast with Einstein and A Brief History of Timekeeping, I needed to make reference to laser cooling as the starting point for modern cesium clocks. I didn’t want to spend ten pages explaining how laser cooling works, though, so spent a little while looking for good pop-science explanations that I could point to in a footnote, but there really aren’t any recent ones. (I ended up punting, and just saying “It’s really neat, but too long to explain here” in both books…) That made me think about writing one, and then to the realization that a lot of the principals from the earliest days of the field are still around, so if I was going to write something I should see if I could get their perspective. Which then turned into pitching this as a feature article for Physics World.

This installment covers the earliest days of the field, and draws mostly on Zoom interviews with Dave Wineland, Bill Phillips, Wayne Itano, John Bjorkholm, Hal Metcalf, and Bob Drullinger. The conversations with Metcalf and Drullinger were a gold mine in terms of colorful quotes; there’s more in those than I could fit in this piece. Bjorkholm was also great to hear from, since I didn’t know much about the Bell Labs piece of the story, and he pointed me to Art Ashkin’s book, which has a lot more (Ashkin is no longer with us, alas). Victor Balykin also sent me some stuff on the Soviet side of the story, which isn’t that well known in the West (sadly, I couldn’t use all that much of it because of the length constraints). I’m really grateful to all of them for taking time to talk to me.

Part 2 of the history (for those who know a bit already, it will cover the MOT and Sisyphus cooling) will run in the fall, and draws more on the interviews with Phillips and Bjorkholm and Drullinger, and also others with Steve Chu and Jean Dalibard. That’s written and with the editors now. Part 3 will get into Bose-Einstein Condensation and Fermi gases; I have to do a bunch more interviews for that.

Ultimately, all this stuff is going to form the basis for a Next Book Project pitch, because I’ve got a wealth of material, and turning what I already have into these short-ish articles was enough fun that I’m happy to give it a go at greater length. So, we’ll see where that goes.

For now, though, here’s the current piece again; please do click the link and read it (you might need to do the free-account thing, but I don’t think there’s a hard paywall on it). I hope you find it enjoyable and informative, and look forward to sharing the next installments when the time comes.

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