re: Attn: Larry J Re: Na lights
Well known fact for all band-emission lighting, including ordinary neons.
The technology of the last 20 years has been to try to smooth the emission, but only partially successful.
NB you also see a "strobe" effect with incandescent lights, but because the decay of emission is a balance between stefan's law of radiation emission, and thermal capacity of the source, it's slower.
And NONE of these are lasers, which can have a very rapid (but not absolute) cut-off...NN