Investigation of the stability of the emission wavelength of a laser with an external neon absorption cell

The optical heterodyne method was used to determine the absolute wavelength of a commercial LG-149-1 helium-neon laser. Measurements were carried out using apparatus containing a laser stabilized by the saturated absorption in ${}^{127}I$, which acted as the reference source. The iodine laser wavelength was determined interferrometrically by comparison with the wavelength of the orange line of ${}^{86}Kr$.