This standard establishes requirements and methods for the specification, evaluation, setup and use of laser interferometers. This standard will explicitly discuss only single-pass optics and a single axis of linear displacement measurement. The standard is currently limited to ionized gas laser interferometer systems. Only single-color lasers will be considered in this version of the laser standard. Single color will include both homodyne systems and heterodyne systems (see Appendix E) where operating frequencies all lie within a Doppler broadened frequency band associated with one specific atomic transition or Zeeman multiplet. Diode laser systems, chirp systems, and two-color interferometers may be included in future versions of this standard. It should be noted that the folded common path comparison technique of this standard could be used to compare any of the above systems to a standard He-Ne laser interferometer.