Plasma cavity ringdown spectroscopy: A powerful technique for elemental measurements and plasma diagnostics

Applications of Plasma–Cavity Ringdown Spectroscopy technique using a pulsed laser as the light source and an inductively coupled plasma (ICP) as the plasma source (Pulsed Laser ICP-CRDS) for elemental and isotopic measurements, as well as high temperature plasma diagnostics have been reviewed. A significantly improved plasma-CRDS system using a low-power microwave-induced plasma (MIP) and a continuous wave (CW) diode laser, namely, Diode Laser MIP-CRDS, has been developed for the first time. The system performance, including ringdown baseline stability, laser source effects, plasma optimization, and detection sensitivity, has been extensively studied using strontium (Sr) as the sample. Evaluation of MIP as an effective atomization/ionization source has been performed by measuring emission spectra of numerous elements, including uranium. A newly designed and fabricated miniature tube-shaped MIP has also been tested. Perspectives of plasma-CRDS-based instrumentation are also presented.