Airborne Continuous Wave Carbon Dioxide Laser for Reconnaissance Applications.
Final rept. 10 Mar 71-28 Feb 73,
HONEYWELL SYSTEMS AND RESEARCH CENTER MINNEAPOLIS MN
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This report describes the design, construction and tests of a stable 100 watt airborne CO2 laser for reconnaissance application. Design emphasis was placed on a high laser frequency and amplitude stability and long-term emission in a P20 line at 10.591 micrometers only. Conventional CO2 lasers generally emit at several lines in the rotation vibration band around 10.6 and 9.6 microns and are thus not feasible for homodyne or heterodyne application. Further design emphasis was placed on beam quality and compact rugged construction. The emitted beam is in the zero order transverse mode TEM sub 00 with a diffraction limited beam spread of 2.5 mrad. Additional collimation by means of an off-axis cassegrain optical system reduces the beam spread to less than 1 mrad. The beam directional stability over a temperature range of 30F was found to be better than 0.2 mrad. The amplitude stability of the laser is better than 5 over the frequency range of 0.05 Hz to 10 MHz. This high degree of stabilization was obtained by constructing the laser cavity from ultra-low expansion quartz ULE quartz which provides a high passive stability without the need for active electronic stabilization. A folding technique for the plasma tubes was used to reduce the overall length of the laser to 57 inches. One cavity mirror is provided with piezoelectric length selection and a second cavity mirror is equipped with an angular alignment capability. Extensive performance tests were made which indicated that the laser meets and exceeds all of the above listed design specifications. Author
- Lasers and Masers
- Military Intelligence