Accurate Wavelength Measurements of the Absorption Lines in H₂O Vapor by a 0.8 µm AlGaAs Laser

The first results of accurate measurements of vacuum wavelengths of six spectral lines of a (2, 1, 1) vibration band in H 2 O were presented using a 0.8 µm AlGaAs laser. For these measurements, the technique known as the coincidence method was employed using a stabilized He–Ne laser as a wavelength standard. Accidental error was kept between 1.7×10 -7 and 5.5×10 -8 . Systematic error was estimated as being 2.0×10 -8 .