We report on the development of a cavity enhanced Thomson scattering (CETS) diagnostic to measure electron density and temperature in weakly ionized discharges. The method uses an intra-cavity beam with average power several orders of magnitude greater than that of illumination sources typically used for Thomson scattering. The increase in illumination source power should result in stronger Thomson signals thereby allowing for highly sensitive measurements with detection limits more than an order of magnitude better than the state of the art. Here, we recap modeling results supporting the viability of the approach and then focus on recent experimental progress towards the CETS diagnostic. We present characterizations of the frequency drift of the optical cavity, and demonstration of cavity frequency locking. The detection system, including triple-pass monochromator and photomultiplier tube, are also discussed. These steps provide a foundation for our continued work to develop the technique for application to weakly ionized discharges.
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