Kinetics and scaling of gain and lasing in a 1-5 kW microwave discharge oxygen iodine laser

Wilson T. Rawlins; Seonkyung Lee; Adam J. Hicks; Ian M. Konen; Emily P. Plumb; David B. Oakes; Steven J. Davis

doi:10.1117/12.847101

3 March 2010 Kinetics and scaling of gain and lasing in a 1-5 kW microwave discharge oxygen iodine laser

Wilson T. Rawlins, Seonkyung Lee, Adam J. Hicks, Ian M. Konen, Emily P. Plumb, David B. Oakes, Steven J. Davis

Proceedings Volume 7581, High Energy/Average Power Lasers and Intense Beam Applications IV; 758104 (2010) https://doi.org/10.1117/12.847101
Event: SPIE LASE, 2010, San Francisco, California, United States

Abstract

Scaling of Electric Oxygen-Iodine Laser (EOIL) systems to higher powers requires extension of electric discharge powers into the kW range and beyond, with high efficiency and singlet oxygen yield. This paper describes the implementation of a moderate-power (1 to 5 kW) microwave discharge at 30 to 70 Torr pressure in a supersonic flow reactor designed for systematic investigations of the scaling of gain and lasing with power and flow conditions. The 2450 MHz microwave discharge is confined near the flow axis by a swirl flow. The discharge effluent, containing active species including O₂(a1▵), O(³P), and O₃, passes through a 2-D flow duct equipped with a supersonic nozzle and cavity. I2 is injected upstream of the supersonic nozzle. The apparatus is water-cooled, and is modular to permit a variety of inlet, nozzle, and optical configurations. A comprehensive suite of optical emission and absorption diagnostics monitors the absolute concentrations of O2(a), O(³P), O₃, I₂, I(²P_3/2), I(²P_1/2), small-signal gain, and temperature in both the subsonic and supersonic flow streams. The experimental results include numerous observations of positive gain and lasing in supersonic flow, and the scaling of gain with a variety of flow and reaction rate conditions. The results are compared with kinetics modeling predictions to highlight key discrepancies as well as areas of agreement. The observed gains are generally lower than the predicted values, due in part to chemical kinetics effects and also due to mixing limitations specific to the reagent injection design. We discuss in detail the observed effects related to O-atom chemistry, and their import for scaling the gain to higher levels. We also will present initial beam quality measurements.

Citation Download Citation

Wilson T. Rawlins, Seonkyung Lee, Adam J. Hicks, Ian M. Konen, Emily P. Plumb, David B. Oakes, and Steven J. Davis "Kinetics and scaling of gain and lasing in a 1-5 kW microwave discharge oxygen iodine laser", Proc. SPIE 7581, High Energy/Average Power Lasers and Intense Beam Applications IV, 758104 (3 March 2010); https://doi.org/10.1117/12.847101

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