Gain Measurements in a Non-Self-Sustained Electric Discharge Pumped Oxygen-Iodine Laser Cavity

Autor: J. W. Rich, K. Fredrickson, K. L. Galbally-Kinney, P. Mulhall, Yurii Utkin, William J. Kessler, W. T. Rawlins, Adam Hicks, Igor Adamovich, Walter R. Lempert, S Tirupathi, Steven J. Davis
Rok vydání: 2006
Předmět:
Zdroj: 37th AIAA Plasmadynamics and Lasers Conference.
DOI: 10.2514/6.2006-3754
Popis: The paper presents results of singlet delta oxygen yield measurements in a high-pressure, nonself-sustained crossed discharge and small signal gain measurement on the iodine atom transition in the M=3 supersonic cavity downstream of the discharge. The results demonstrate operation of a stable and diffuse crossed discharge in O2 – He mixtures at pressures of up to P0=120 torr and discharge powers of up to 2.2 kW. The reduced electric field in the sustainer discharge in O2-He flows ranges from 0.6·10 -16 V·cm 2 to 1.2·10 -16 V·cm 2 . Static pressure measurements in a supersonic cavity show that a steady-state M=3 flow in the cavity can be sustained for up to 20 seconds. Singlet delta oxygen yield in the discharge, up to 5.0-5.7% at the discharge temperatures of 400-420 K, was inferred from the integrated intensity of the (0,0) band of the O2(a 1 ∆→X 3 Σ) infrared emission spectra calibrated using a blackbody source. The results show that O2(a 1 ∆) yield increases with the discharge power and remain nearly independent of the O2 fraction in the mixture (in the 10-20% range). These results suggest that the measured singlet delta oxygen yield would exceed the threshold yield at the flow temperature achieved in the supersonic cavity, T=120 K, by about a factor of three. Indeed, gain measurements clearly confirmed this prediction. Preliminary measurements demonstrate gains of up to 0.01%/cm measured in the supersonic cavity at these conditions.
Databáze: OpenAIRE