Radio frequency excited carbon dioxide metal waveguide laser
A new type of waveguide laser is investigated. The waveguide is a single surface concave metal waveguide that also doubles as the grounded electrode in a radio frequency excited gaseous discharge. Theoretical studies on the modes and frequency characteristics of the laser have been performed. The modes of the waveguide are shown to be well represented by Hermite-Gaussian functions parallel to the waveguide and by the Airy function perpendicular to the waveguide. The output of the laser is shown to evolve approximately into an elliptical Gaussian beam in the far field. Numerical calculations for a metal waveguide carbon dioxide laser operating at 10.6 ..mu..m indicate that its operating efficiency and mode stability are comparable to conventional dielectric waveguide carbon dioxide lasers. Two metal waveguide carbon dioxide lasers have been built to verify the results of the theoretical studies. One laser is designed to run multimode. The frequency differences between longitudinal and transverse modes have been measured with a HgCdTe photodiode detector and are found to be in agreement with theory. The resistance and capacitance of the laser have been measured at RF frequencies and found to be roughly the values of the other RF excited lasers. The other laser is designed to run lowest transverse order mode. Near and far field scans of the laser output have been taken and shown to be in agreement with computer calculations. Except with severe misalignment, the laser operates only in the lowest order transverse mode. Both lasers demonstrate output powers in the one to two watt range with operating efficiencies comparable to conventional CO/sub 2/ lasers.
- OSTI ID:
- 6049832
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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