Determination of oxygen atom concentrations by cavity ring-down spectroscopy

Cavity ring-down spectroscopy (CRDS) has been applied to the detection of oxygen atoms, on the highly forbidden 1D2 ← 3P2 line at 630.030 nm. Results are presented for CRDS detection in a discharge flow system, in which the atoms are prepared by a microwave discharge of N2O/Ar or O2. Comparison of concentrations determined by CRDS and chemical titration by NO2 is made. CRDS is found to be a non-intrusive technique for the determination of oxygen atom concentrations in the range of 1014 atoms cm−3 and higher, with an estimated accuracy of ⩽20%.