CO2 Green Laser?

I have recently gotten the book ELECTRONIC GADGETS FOR THE EVIL GENIUS. There are various instructions on building green lasers. However, there is a section that explains how to build a 20 Watt (or something like that) Class IV laser. I was wondering if this was possible and if anybody's ever tried?

Yeah CO2 lasers are pretty easy to build and work great. They are of the more dangerous lasers to own. The output is in the mid infrared region at 10,600nm. Safety glasses are an absolute must.

Yeah, I was actually surprised when I saw that it was like 20 Watts or something like that. I really don't know a lot about building CO2 lasers but in the instructions it said that to build it, it would cost about 500. I really didn't want to try to waste 500 for something I have no idea how to build. i have never seen a CO2 laser though.