I'm building a laser cutter/engraver using a 40W CO2 laser, and I want to provide a window in the case so I can monitor things when the laser is on.
I have various sheets of transparent plastic, but of course I want to make sure that any stray laser energy doesn't pass through the window and blind me.
I know that the wavelength of the laser output is 10600 nm (invisible infra-red), but I don't know how to determine whether a given candidate material is opaque enough to be acceptable.
I've looked for this information online (assuming that it would be in the specifications provided by the manufacturer), and I've run into two problems with that approach:
- This information is rarely in the specs I've been able to find
- In many cases I have scrap/donated material of unknown origin, so rather than rely on specs for what I THINK the material is, I'd much rather TEST.
Can anyone recommend a method of assuring that a given piece of test polycarb, Plexiglas, etc. is opaque at 10,600 nm?
NOTE: Any stray laser energy that bounces up from the bed would be far too diffuse to melt this material. However, it might be strong enough to damage a retina if it passed through undiminished.