Zero-Power-Gain Measurements in CW HF(DF) Laser by Means of Fast-Scan Technique.
AEROSPACE CORP EL SEGUNDO CALIF AEROPHYSICS LAB
Pagination or Media Count:
An improved technique for measuring zero-power gain in a cw HF-DF chemical laser has been developed in which a cw HFDF single-line, frequency-stabilized TEM00 mode probe laser is used. Through use of a flat rotating mirror and focusing elements, the streamwise distribution of zero-power gain was scanned at a rate of approximately 1 mmmicrosec with a spatial resolution of approximately 1 mm. The method, therefore, permits real-time observations of the streamwise gain profile. The zero-power-gain profile was observed for two-arc-driven chemical-laser nozzles with both HF and DF active species. The nozzles consisted of a 36-slit array with perforated tube H2 injectors and a 55-slit array with uniform H2 injection. The F2 nozzle exit widths were 3.8 and 3.0 mm, respectively, and operated at an exit pressure of approximately 3 to 6 Torr. For the 36-slit nozzle, a peak line-center gain of 10cm was measured at x 6 mm on the maximum-gain P24 HF transition. A peak gain of approximately 10cm was also measured on the P14 HF transition at x 1 cm. For DF, a peak gain of 4.7cm was measured on the maximum gain P26 transition at x 6 mm with the same molar flow rates as the HF measurements.
- Lasers and Masers
- Fluid Mechanics