Yvonne Carts-Powell

First Free-Electron Light Source on a Chip

In Uncategorized on July 23, 2009 at 1:09 pm

Light-well This is so so cool! Perhaps you need to be a laser geek (as I am) to appreciate this, properly: One of MIT Technology Review‘s blogs covers the Physics arXiv of preprints, and includes this entry:First Free-Electron Light Source on a Chip.

The cool thing about free-electron lasers is that you can tune their output to any wavelength you’d like. The uncool thing is that they have been huge, heavy, expensive beasts. But a paper in the physics arXiv suggests that a free-electron light source (not a laser, or at least not yet) could be made on a chip. This blog entry explains it well.

As my husband would say: this is awesome o’possum!

We’ll see if it goes anywhere from here.

I have reason to be dubious of free-electron news stories. Back in 1998, an organization of science writers convinced a professor from Boston University, to give a talk on using free-electron lasers in military applications. He was spinning tales of how, if these lasers could be carried in a backpack, they could have all sorts of uses treating wounded soldiers on the battlefield.

I was sitting in the back of the room with  Sunny Bains (who is a very smart, very sharp scientist and journalist), when she’d had enough of this nonsense. (Disclosure: I do some work on a freelance basis for Sunny.) Their exchange went something like this:

Q: Wasn’t it true that today’s free-electron lasers were very large — room-sized or even bigger?
A:Yes, that was true.

Q: When did the professor think that free-electron lasers would become small enough that they could be carried?
A: Maybe the year he (the professor) planned to retire — specifically because it was the year he planned to retire.

Q: So why was he giving a talk about devices that were impossible in the near term?
A: Because the organizers of this event had asked him to.

It was a classic case of the tale wagging the dog. Even worse, some of the science writers in the room went ahead and wrote the story anyway,  making it sound like small free-electron lasers would be possible in a year or two.   It was not a proud day for science journalism.


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