Plasma magnetic field measurement by intracavity absorption

Dye laser intracavity absorption (ICA) as a potential diagnostic for plasma or neutral beam systems was studied. For magnetic field measurements it is necessary to make Zeeman effect measurements on the resonance transition of atomic lithium on a millisecond time scale. To do this it is necessary to sweep the dye laser in wavelength at a rapid rate so that the absorber can be sampled many times during the measurement. It is indicated that the ICA signal becomes small at high sweep rates limiting the rate at which such sweeping may be carried out. It may be possible to avoid this limitation by chopping the pump laser. An ICA system using a dye cell is designed, and experiments involve the observation of ICA in a ring dye laser are discussed.