Abstract

We have previously reported [1] enhanced fluorescence of the CII, 5d-3p transition at 213.8 nm, when the 5d-2p transition is selectively pumped by A1III, 56 nm line radiation. The CII ions are produced in a carbon vacuum arc discharge, while the A1III pump ions are created in an adjacent, laser-produced plasma. Collisional coupling of the pumped, 5d level in CII to the 5f level was verified [2] by observation of enhanced fluorescence at 299.3 nm on the CII, 5f-3d transition. This paper reports simultaneous observation of four different wavelengths in CII, in order to characterize the optical pumping process and the subsequent collisional-radiative kinetics. Measurements are described of electron density (n_e) and electron temperature (T_e) in the C vacuum arc. The measured values of n_e and T_e are inputs to a time dependent, collisional-radiative model for the CII level populations. Model predictions of the expected fluorescence enhancement, the coupling of the pumped 5d level to other levels in CII, and various loss rates are compared with experiments. The possibility of producing a laser in CII using this scheme is examined. Other candidate pairs for optically pumped, XUV wavelength lasers are presented and discussed.

© 1984 Optical Society of America