I really want to build a laser that is capable of causeing air ionization in a pointer sized package. I'm thinking somesort of q switched diode pumped solid state laser. The plasma would only need to form at the focal point of the lens that I would use with the device. I've seen some similar devices that are textbook sized, but I want to know if its possible to make somehing smaller. Also important is that it has a high repition rate <500 Hz. Over 1000 Hz would be great. Don't worry very much about power requirement, I just care about the compactness. I want to ask on these forums before I spend all my time trying to understand how to make one.