Can Helium-Neon be made to lase at other than the usual wavelength?
The Sargent Welch catalog has a green laser (550 nm) that they claim is a
solid state diode laser (this makes sense to me). But the company that
makes it, Metrologic, has a similar picture in its catalog but specifically
claims (twice) that it is a green _He-Ne_ laser. Somebody is confused, and
it could be me.