Table 2: Comparison of the instrument performance of a previously reported CRD spectrometer with those used in this work.

QuantityBrumfield et al. [17] (cw-QCL CRDS)This work (cw-QCL-based CRDS setup)This work (CALOS setup)

/μs10725
σ τ/ /14.7 × 10−22.8 × 10−28.0 × 10−3
σ α/cm−11.58 × 10−71.33 × 10−71.07 × 10−8
/Hz10151080
/cm−1 Hz−1/25.06 × 10−83.44 × 10−83.26 × 10−10

Quantities: → average ring-down time for an empty cavity/nonabsorbing gas, σ α→ base line absorption coefficient, → ring-down event rate, → sensitivity.