This seems to be just about the simplest homebuilt laser you can make: a TEA nitrogen laser. TEA stands for Transverse Electrical discharge at Atmospheric pressure. It requires no vacuum pumps or glasswork. Someday, my desire for mad science will lead me here…
If you are interested in TEA N2 lasers, you may find my
website handy. I tested my design against a commertial unit and
it performs favorably well.