Optical pumping transverse magnetization

In this chapter we shall be concerned mainly with the principles of the technique, the effect of relaxation processes, and magnetic resonance transitions between Zeeman sub-levels. We shall therefore initially describe the experiments in terms of the populations of the ground state sub-levels. The discussion of the effects of phase coherence (Hertzian coherence) and experiments involving transverse pumping is reserved until section 17.8. Moreover the application of optical pumping methods to the investigation of hyperfine intervals and the measurement of nuclear moments is postponed until Chapter 18, as are the applications of this technique in devices such as magnetometers, atomic clocks, and masers. 

Transverse magnetization and Hertzian ooherenee in optical pumping experiments... 

The derivation of equation (17.21) for the width of the magnetic resonance signals observed in an optical pumping experiment is now quite straight-forward. A study of the time-dependent solutions of equation (17.55) (Problems 17.9 and 17.10) leads to equations which we have discussed earlier in connection with the measurement of the longitudinal and transverse relaxation times in transient experiments. ... 

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