Abstract

We have observed changes in the conductivity of a helium radio-frequency discharge when the helium metastable atoms are excited with an IR, tunable laser at the resonance wavelength. The plasma conductivity is a function of the electron density in the cell and is modified by either of two collisional processes: He^m + e → He⁺ + 2e or He^m + He^m → He⁺ + He + e. The first case is observed by varying the intensity of the resonant laser light, thus varying the metastable density. In the second case, the cross section for the reaction is modulated by varying the spin polarization of the metastable atoms by optical pumping.

© 1989 Optical Society of America

Hyperfine structure studies of ¹⁷⁵Lu by laser optogalvanic spectroscopy

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