He-Ne Lasers
Helium-Neon (HeNe) lasers are the work horse of the optics industry and are available in single or multi-mode output and with polarized or unpolarized output. They have long been used as a stable 632.8nm (red) source and are often used as an alignment laser for infrared and UV optics because of their low cost and availability. They have also found their way in many uses such as confocal laser scanning microscopy, spectroscopy, interferometry, and general research. Custom versions are available at other He-Ne lines in the green and yellow.