It would be too dangerous, lasers have a very long range, if you are not careful you might "saw off" someones leg (or multiple someones legs) by getting distracted by a beautiful girl or something. If the laser saw would be portable at all, needing that much power.

gerbenr, I'll admit I don't know much about lasers and my idea might be more like a Star Wars fantasy but since my original post I've done some googling re: lasers and I've found that some are used in surgery and in etching -- not just cutting -- so apparently there is some depth control.

A couple of reasons, really. One, they're expensive. CO2 lasers require a lot of parts and some rare and dangerous materials during construction. Two, they are hard to operate. They require a vacuum pump, a tank of CO2, and some electricty. A lot of electricity, actually. They're hard to control. You have a very hot beam that's going to burn whatever's on the other end. How long do you pulse, and how do you move it to get a uniform cut? That takes CNC. Lasers are indiscriminite - they cut through whatever, and need to sit over a liquid solution designed to absorb and dissipate the heat.

And to top it all off, they're incredibly dangerous. It's an invisible beam that will start burning through whatever gets in front of it. Even the dot starts as invisible to our eye; but it still burns us. We see the black body radiation generated from the heat. Very, very dangerous.

Unfortunately and lastly, they're simply nowhere near as flexible as your needs require.

I think this idea has more potential that the other comments suggest. A home laser cutter would probably not be all that powerful, both for safety and for cost. Cutting off a leg would take a long time, and so wouldn't be a likely problem. Of course it would also take a long time to cut what you want to cut, but if you have no other tool for the job, then you'll just have to be patient. Low power would also make it easier to control the depth of the cut.

As for the beam being invisible, while the cutting beam may be invisible, it is common to have a pointer beam that is visible. The pointer is first turned on and used to aim the tool. Then the actual cutting beam is activated. The cutting beam and pointing beam can be set to follow the exact same path, so where the pointing beam goes, the cutting beam will be in the exact same place. There would be no reason to use a CO2 laser. A cheaper solid state laser would be more sensible.

This sort of tool would not be suitable for excavating holes in the ground, but for cutting thin material it could be workable.

The government requires high powered lasers to be enclosed, for good reason. Whatever they do to the material can be done to your eyeballs.

Bulky. Expensive. Powerful. Very powerful provided the power supply is enough, some are so powerful that if you were to pass a popsicle stick in front of the beam as fast as you could muster, the popsicle stick would be in half before you knew what happened. Probably the main reason.

helloiam,If a laser is too powerful & dangerous only if it has a great power supply, why not simply give it a smaller power source. Are there no dentists reading this web site who can clue me in as to how dentists can use lasers to drill teeth without cutting a hole in the patients jaw? (Or a dental laser sales rep :) They also use lasers to do eye surgery don't they? Isn't that what Lasik is?