What’s the application? Using lasers to cut and/or cauterize tissue during surgical procedures, instead of the traditional very small very sharp knives.

What problem(s) is it the solution to? 1) “How can we do surgery without touching the tissues being operated on?” 2) “How can I get rid of these annoying glasses/contact lenses?”

How does it work? First, you strap a device to your head that lets you shoot laser beams from your forehead, like one of the X-Men. then you use a magnifying glass to focus it to where it needs to be. Like so:

(I’m not sure exactly what sort of procedure that is, but I really hope that’s not how they do the surgeries where they re-shape the cornea…)

The basic idea of laser surgery is sort of similar to the previous application, namely, if you focus a laser beam down to a very small spot, it will deliver a great deal of energy to that spot. If that spot happens to be on a bit of human tissue, it can get hot enough to blast the target cells into vapor.

This allows you to make extremely precise cuts in human tissue, with the bonus effect of keeping everything involved nice and sterile, as there is no contact between a physical device that might carry microbes and the tissue in question– just light. The heat involved also tends to kill harmful microscopic critters that are already hanging around, and sometimes to cauterize blood vessles, keeping everything much cleaner.

The default sort of laser surgery that people think of is LASIK vision correction, which is explained in slightly gross detail with step-by-step images here. The idea is to use a powerful laser to blast away bits of the cornea, reshaping it so as to move the focal point to a location closer to the retina, thus improving the patient’s vision.

There are a bunch of other non-LASIK eye surgeries done with lasers, as well. It’s also used for surgeries on other parts of the body, but it’s damnably difficult to sort those applications from the nine billion pages about laser eye surgery. A partial and not very detailed list can be found here, which gives you the basic idea.

Why are lasers essential? Once again, the key to the whole thing is getting a very intense pulse of light directed to a very small point. While I suppose it’s theoretically possible to do this sort of thing with a great big lens on a sunny day, lasers are really the way to go. Especially if you’re in a climate where it’s often cloudy.

Why is it cool? Dude, surgery with lasers!

As noted above, laser scalpels offer a number of nice properties that help reduce the chance of serious complications– reduced bleeding, lower risk of infection, greater precision, etc. And, as a bonus, when you’re done with surgery you can breathe some ether, crank up the Pink Floyd, and enjoy a homemade light show.

Why isn’t it cool enough? Surgical applications of lasers are still kind of limited, and mostly reproduce things that can also be done with a regular scalpel. Also, the radio and tv spots run by some LASIK doctors are pretty annoying.