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Studies of photoexcitation for extreme ultraviolet lasers

Thesis/Dissertation ·
OSTI ID:6946923
A laser-produced plasma facility was constructed that is suitable for exciting very high densities of excited state ions and atoms for the production of extreme-ultraviolet lasers. This facility includes a high power Nd:YAG-glass system, which generates laser pulses at 1.06 ..mu..m with a duration of 0.1 to 1 ns with energies of 2 to 20 Joules, and a dye laser system which can produce tunable laser pulses of 20 ps duration with energies of 1 to 3 mJ. A new synchronously pumped oscillator was designed for the dye laser system to provide high power, broadly tunable, picosecond pulses would be appropriate for transferring or measuring excited-state populations. This facility has been used to generate x-rays from a laser-produced plasma on a tantalum target in order to photoionize core electrons in Li vapor to produce excited Li ions. Measurements of the Li/sup +/(1s2s)/sup 3/S metastable ion and Li/sup +/(1s3s)/sup 3/S ion densities were performed to study the dependences of these populations on time, Li pressure, laser energy, and distance from the target. Metastable densities as high as 3 x 10/sup 15/ cm/sup -3/ were achieved in the Li/sup +/ (1s2d)/sup 3/S state at 2 mm from the target with 2.3 joules of laser energy.
Research Organization:
Stanford Univ., CA (USA)
OSTI ID:
6946923
Country of Publication:
United States
Language:
English