High repetition rate continuously tunable CO2 laser system investigation.

Abstract

The purpose of this thesis was to investigate certain factors important for the operation of a high repetition rate continuously tunable CO2 laser. The tuning range of specific importance for this research program was the R30 region within the ten micron band, since this frequency is of great importance for the laser isotope separation of uranium. This research program focused on: (i) Lowering the pressure at which viable continuous tunability could be achieved. {ii)Resonator design and analysis. {iii)Investigating the feasibility of using water capacitors in a high repetition rate laser system. A theoretical as well as an experimental investigation was done into the use of CO2 isotopes to lower the pressure at which continuous tunability in the R30, ten micron band could be achieved. A theoretical analysis was done into the use of a three mirror resonator with an etalon and a grating to ensure single longitudinal mode tuning in the R30 region. Such a resonator was designed and experimental results obtained were compared

with those predicted by the theoretical analysis. A study was done into the use of water as a dielectric medium in a high repetition rate pulse power supply. A mathematical model, describing the electric breakdown of water,was developed. This was compared with published experimental results. Certain parameters important for the design of a water capacitor were experimentally measured. These include the intrinsic time constant,dielectric constant and resistivity of the water. A design proposal as well as a comparison between a water capacitor and other capacitor technologies are presented.