Measurements of OH radicals in low temperature atmospheric plasmas using pulsed- and cw-CRDS techniques

Summary form only given. OH radicals have electronic transitions in the UV and overtone spectra in the NIR. Absolute number density of OH radicals can be quantified by using high sensitivity pulsed-cavity ringdown spectroscopy (CRDS) and diode laser continuous wave (cw)-CRDS techniques. However, the applicability of these two sets of CRDS techniques to different plasma sources (including discharges) is plasma-type-dependent and has not been fully investigated. We have employed the pulsed- and cw-CRDS techniques to quantify OH radicals created in an atmospheric microwave induced plasma (MIP), an MlP-jet, and an AC discharge. We present the results and discuss for the first time on the topic of the applicability of CRDS to OH measurements in different plasmas.