Supersonic flow, low-temperature ultraviolet, and visible high-powered lasers
Abstract
Several high-power ultraviolet and visible laser emissions have been achieved from excimer (XeF), ionic (NeII), and atomic (FI) electronic transitions. These emissions result from the electron beam excitation of mixtures of rare gases and halogenated compounds in supersonic flow at very low temperatures (65-120 K) and high density (up to 2 amagats). Supersonic flow was produced with a Ludwieg tube pulsed blowdown and was achieved because of aerodynamic cooling temperature conditions which are not easily obtainable with a thermal exchanger but which are favorable for lasers. Characteristics and specificity of the laser emissions obtained with the supersonic blowdown device are detailed. The effect of cooling on both the population of the upper and lower laser levels and the absorption phenomena by excited species will be discussed. Although laser action in the ultraviolet range from a high-pressure supersonic flow has been demonstrated, the study of aerodynamic losses must be carefully undertaken within the framework of lasers with high-powered continuous waves, pulsed high-repetition-rate ultraviolet rays, or visible high-density supersonic flow. Preliminary results of an interferometric study of the density variations produced by electron beam excitation of the flow are given.
- Publication:
-
Combustion in Reactive Systems; 7th International Colloquium on Gasdynamics of Explosions and Reactive Systems
- Pub Date:
- 1981
- Bibcode:
- 1981crs..proc...75F
- Keywords:
-
- Gas Mixtures;
- Gasdynamic Lasers;
- High Power Lasers;
- Molecular Excitation;
- Supersonic Flow;
- Ultraviolet Lasers;
- Aerothermochemistry;
- Continuous Wave Lasers;
- Electron Beams;
- Electron Transitions;
- Excimer Lasers;
- Low Temperature;
- Particle Interactions;
- Rare Gases;
- Temperature Effects;
- Lasers and Masers