Investigation of rf excited CO2 slab laser discharges by mass spectrometry and optical spectroscopy of CO and N2 emission bands
Abstract
A problem associated with sealed off CO2 lasers is the partial dissociation of CO2 in an electrical discharge. To achieve a long operation lifetime in a sealed off rf excited slab laser system it is necessary to know the main discharge parameters, the discharge behaviour and the plasma chemistry as a function of different gas compositions, gas contaminations and electrode surface layers. For this purpose we measure with high spatial resolution the emission of CO and N2 molecular bands and He lines emitted in the visible and UV spectral range from slab discharges operated at 80 MHz. Measurements are made in a test chamber and CO2 slab laser modules with 100 W and 2 kW output power for different defined contaminations of water vapor. The gas temperature profiles and spatial distribution of the power input across the discharge gap are determined. The time resolved development of the gas composition is recorded by mass spectrometry. For the first time, the influence of controlled water vapor contaminations is measured quantitatively for different electrode coatings and different mixtures of the filling gas.
- Publication:
-
APS Annual Gaseous Electronics Meeting Abstracts
- Pub Date:
- October 1997
- Bibcode:
- 1997APS..GEC.MW206B