Stabilization of the power of a He-Ne laser

The design and principles of operation of a laser stabilization system are discussed along with the basic circuit of the discriminator-amplifier used in the system. The stabilization efficiency is estimated by measuring the intensity of the operating beam with a photomultiplier. It is shown that laser radiation is maintained at the same level for several hours within 0.5%. In addition, the discriminator-amplifier is found to be practically insensitive to fluctuations in room temperature.