Supersonic COIL with iodine injection in transonic and supersonic sections of the nozzle

摘要

We report on a detailed experimental study of the gain and temperature in the cavity of a supersonic chemical oxygen-iodine laser operating without primary buffer gas and on preliminary power measurements in this laser. In particular, a study is carried out to find optimal values of the flow parameters corresponding to the maximum gain. The measurements are performed for slit nozzles with different numbers and positions of iodine injection holes. Using a diode laser based diagnostic, the gain and temperature in the cavity are studied. Maximum gain of 0.73percent/cm is obtained at chlorine and secondary nitrogen flow rates of 15 mmole/s and 7 mmole/s, respectively, for a slit nozzle with transonic injection of iodine. Preliminary power measurements are performed. For slit nozzle with iodine injection in the diverging part of the nozzle output power of 287 W with chemical efficiency of 21percent was measured at 15.1 mmole/s of Cl_2 with no primary buffer gas. This is the highest reported chemical efficiency of a supersonic COIL operating without primary buffer gas.