- 15.6: The Helium-Neon Laser
- The He-Ne laser was the first continuous wave (cw) laser invented. A few months after Maiman announced his invention of the pulsed ruby laser, Ali Javan and his associates W. R. Bennet and D. R. Herriott announced their creation of a cw He-Ne laser. This gas laser is a four-level laser that use helium atoms to excite neon atoms. It is the atomic transitions in the neon that produces the laser light. The most commonly used neon transition in these lasers produces red light at 632.8 nm.
Thumbnail: Six commercial lasers in operation, showing the range of different colored light beams that can be produced, from red to violet. From the top, the wavelengths of light are: 660 nm, 635 nm, 532 nm, 520 nm, 445 nm, and 405 nm. Manufactured by Q-line. (CC BY-SA 3.0 Unported; Sariling gawa via Wikipedia)