It is difficult to apply Laser Induced Fluorescence (LIF) method for optically thick plasma because its fluorescence profile is distorted by re-absorption. In this study, LIF was combined with Laser Absorption Spectroscopy (LAS) to measure spatially resolved translational temperature in an optically thick argon plume. By utilizing absorption data of a probe laser beam through the plume, distortion of LIF profile was corrected, and accurate translational temperature was obtained. Although translational temperature without correction was 2400 ± 300K, corrected translational temperature was estimated at 1300 ± 200 K. This crucial difference indicates that the effect of re-absorption must be in consideration in optically thick plasma.
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