Helium neon (HeNe) lasers are gas lasers which use a mixture of helium and neon to achieve optical gain. All lasers consist of three components: an energy source (or pump), a gain medium, and an ...

Helium-neon lasers may be little more than glorified neon signs, but there’s just something about that glowing glass tube that makes the whole process of stimulated emission easier to understand.

Helium cadmium (HeCd) lasers are members of the same laser family as helium neon (HeNe) lasers, and they are the only relatively economical, continuous-wave sources for violet (442 nm) and ultraviolet ...