Cathode Limited Operation of Transversely Excited Carbon Dioxide Channel Waveguide Laser.
Abstract
The discharge, gain and oscillator characteristics of transversely excited CO2 gas mixes was investigated under pulsed and CW conditions. A 1.6 mm square channel having a segmented upper electrode structure and a solid copper electrode with dielectric sidewalls formed the discharge chamber. Resistive loading of the individual discharge segments precluded arcing and insured glow discharges. However, the discharges were not wall confined except at pressures below 100 Torr, thereby reducing wall cooling and complete volumetric excitation. For low pressures a large fraction of the energy was deposited in the cathode fall region. At higher pressures the luminous glow discharge column narrowed and the ratio of the power dissipated in the cathode fall region decreased. However, the total power and power densities deposited in this region increased. The high electric fields and gas temperatures in this region dissociate and ionize molecules thereby limiting sealed-off lifetimes. Diffusion of heat into the adjoining gas creates turbulence and limits the gain. Detailed analysis of the negative aspects of the cathode fall region and nonuniform volume excitation suggests those areas where improvement is most essential. Certain improvements can be obtained by revising the construction of these devices. It remains essential, however, to limit the negative aspects of the cathode fall region and the Malter effect is suggested as one possible means of accomplishing this. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1977
- Accession Number
- ADA044052
Entities
People
- A. Papayoanou
Organizations
- United States Army Communications-Electronics Command