Wednesday, May 24, 2006

Here's an expression that really bothers me: "focus like a laser". (By the way, I know there is continuing controversy over whether to put a period, or other punctuation, inside or outside quotes. In my copy-editing class in 2000, we learned that the American habit it to put it inside, while the British tend to put it outside. My rule is: if the thing in quotes is just an object, a thing I am talking about, such as a word or phrase whose meaning I'm overanalyzing, the period goes outside. If the phrase actually forms part of the sentence grammatically, as in: Ross Perot said that when it came to the economy, he would "focus like a laser.") So yes, I first heard the expression from Perot in 1992. I suppose I could use Lexis-Nexis to find an earlier cite. I'll start doing things like that eventually; right now, I'm just writing from my head. Anyway, now everyone seems to say it. There's just one problem: lasers don't really focus. People seem to think the reason that lasers can burn holes in steel is that they are highly focused. But they are getting confused with using light to, say, set paper on fire, using a magnifying glass or Piggy's glasses in "Lord of the Flies". When light is focused, it is bent by a (convex) lens, so that the rays travel at an angle to converge at a certain point. If you put something at that point, the energy of the rays will be concentrated on it. But lasers basically travel in straight lines. They concentrate lots of energy on one point because the light is coherent, meaning the waveforms are all in step, and because a lot of energy is being pumped into the laser. I mean, yes, you can send a laser through a lens, but lasers by themselves aren't focused. So, let's focus like rays through a magnifying glass on getting this right.

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