Re: Reinventing the Wheel
I have heard of mercury vapor arclamps. They are used for spectrophotometer biofluorescence experiments, not because they are efficient, but because a significantly large percentage of the light they emit is coherent like laser light, but it's cheaper than a real laser.
Not to sound hypcritical - after all most fluorescent tubes contain mercury - but I avoided doing an analysis of mercury vapor arclamps because they contain mercury in a potentially more toxic form. And I don't really feel like doing one now just because I am inherently lazy. :)
Actually mercury lamps are metal halide are they not? Mercury is a metal right? But pure sodium is a metal too, eh? I guess the spectra could be different?