I don’t have any deeper information about this, but this article pretty much sums up what went through my head as I read that piece:
In Arthur C. Clarke’s 1950s science fiction novel Sands of Mars, written in those pre-laser days, someone has a large photoflash unit that puts out an impressive amount of energy, and someone remarks that he wouldn’t want to be around if anything should happen to the battery or the capacitor, which have enough stored energy to make a good-sized bomb. That goes double for this gun.
Lasers are intrinsically inefficient devices, meaning that they have to lose a portion of their energy – inevitably to heat – in order to achieve the population inversion necessary to make them work*. This means that
a.) you have to have a lot of energy to start with
b.) Your raygun is going to get awfully hot after a couple of shots.
Add to this the fact that the human body contains a LOT of water that has to be boiled off in order to carbonize it. Even locally. That means you really do need a lot of oomph to do damage. It’s possible (I’ve seen a CO2 laser cut through meat, or an argon fluoride laser punch cookie-cutter holes in things), but it takes a lot of doing.
**Although a lot of incredibly high efficiency lasers have been developed, they generally have to be driven by another, much lower efficiency laser, so it doesn’t help. You can build a gas laser in which mixing gases results in a combination already in an excited state, with a built-in population inversion, but that requires huge chambers for holding and mixing the gas. Not a hand weapon.
