HIGH POWER GAS LASER RESEARCH.
Final technical rept. 31 May 67-30 Apr 68,
RAYTHEON CO WALTHAM MASS RESEARCH DIV
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This report discusses the extension of the previously developed high power cw gas laser technology into the multikilowatt range. A continuous output of 8.8 kW at 13 percent efficiency has been obtained from a multi-folded, flowing gas dc-excited CO2 laser using a periodically refocussed optical system and a superradiant mode of operation. The performance of this laser indicated clearly the need for better window materials for use at high power levels. With the recognition of the output window as the major obstacle to very high power CO2 laser performance, the principal goal of the program was chosen to be the mastery of the window problems. This involved detailed surveys of potential candidate materials, careful measurements of the optical absorption coefficients at 10.6 micrometers and extensive destructive testing of various windows by means of the focussed and unfocussed beam of the 8.8 kW laser. The results of these studies suggest two materials as outstanding window materials, the salt KCl and the semiconductor GaAs. Each has its own particular advantages and disadvantages. By the use of these materials, operation of CO2 lasers with power outputs in the range of tens to hundreds of kilowatts now seems possible. Author
- Lasers and Masers