['Helium Neon Laser: The first CW system was the helium neon (HeNe) gas mixture. ... ', 'Argon, Krypton, and Xenon Ion Lasers. ... ', 'Carbon Dioxide Laser. ... ', 'ND:YAG Laser Systems: ... ', 'Excimer Lasers: ... ', 'Semiconductor Diode Lasers. ... ', 'Other Lasers:']