Zeeman effect longitudinal field

In order to use the Zeeman effect for background correction [306] several approaches can be applied (Fig. 87) [307]. A magnetic field around the primary source or around the atom reservoir can be provided, by which either the atomic emission lines or the absorption lines are subjected to Zeeman splitting. Use can be made of a constant transverse field and the absorption for the it- and the -components measured alternately with the aid of a polarizer and a rotating analyzer. However, an ac longitudinal field can be used and with the aid of a static polarizer only the cr-components are measured, once at zero and once at maximum field strength. 

These theoretical statements can be tested directly in the case of the normal Zeeman effect. As is well Imown, on transverse observation (at right angles to the magnetic field) we see the normal Lorentz triplet, i.e. a splitting-up into three components. Of these the central one, which corresponds to the transition m -> m and is therefore not displaced, is polarized in the direction of the magnetic field, while the two other components, corresponding to the transitions m i 1 are transversally polarized. In longitudinal observations the undisplaced component disappears and we see only the two displaced components, which, as theory requires, are circularly polarized. 

FIG. 2. Principle of Zeeman effect background correction, using a pulsed, longitudinal magnetic field at the atomizer, = emission line profile, (a) Magnetic field off. (b) Magnetic field on (Courtesy of Perkin-Elmer). 

Instead inside the laser cavity the sample can be also placed outside between two crossed polarizers (Fig.6.31). In a longitudinal magnetic field the plane of polarization of the transmitted light is turned, due to the Faraday effect, if its frequency w coincides with one of the allowed Zeeman transi-... 

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