Extreme Ultraviolet Emission Spectroscopy of Atoms and Laser Applications.
Abstract
Many XUV laser schemes are limited by the short autoionizing life-times of atomic states which lie above the ionization threshold. Two approaches to dealing with this problem are presented. In the first, the properties of a class of levels known as "quasi-metastable" levels are investigated. These levels are relatively metastable against autoionization due to a number of selection rules and possess substantial branching ratios for radiation in the XUV. Autoionizing and radiative rates are calculated for quasi-metastable levels in alkali atoms with a Hartree-Fock code. The results of emission spectra confirming the high radiative yield of these states is presented. Implications for several proposed XUV laser schemes are discussed. In the second approach we examine the use of MMM super Coster-Kronig transitions in Zn to produce inversion and gain on several transitions in Zn III between 56.8 nm and 133.8 nm. The super Coster-Kronig transition converts 90% of Zn II ions created by photoionization in a laser -produced plasma into Zn III 3d('8) 4s('2) ions at an energy of (TURN) 65 eV. Several laser schemes utilizing this selective autoionization process are discussed. Experimental verification of the high super Coster-Kronig branching ratio in a microwave discharge cell is presented.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- December 1985
- Bibcode:
- 1985PhDT........19M
- Keywords:
-
- Physics: Atomic;
- Atoms;
- Extreme Ultraviolet Radiation;
- Laser Applications;
- Spectral Emission;
- Spectroscopy;
- Hartree Approximation;
- Laser Plasmas;
- Metastable State;
- Photoionization;
- Zinc;
- Atomic and Molecular Physics