Frequency stabilization of a green He-Ne laser

A new process for stabilizing the frequency of commercially available 543-nm He-Ne lasers is described. The stabilization method is based on anomalous dispersion of the gain medium. A total of four green lasers have been stabilized-two at the National Institute of Standards and Technology and two at the Institute of Scientific Instruments of the Czech Academy of Sciences-making it possible to study frequency variations of the lasers relative to each other. We have also stabilized a 633-nm laser by the use of the same method used for 543 nm.