Collinear two-color saturation spectroscopy in CN A–X (1–0) and (2–0) bands.

Highlights: [•] We report two-color sub-Doppler saturation spectra of CN in the red A–X system. [•] Hyperfine constants derived for υ =1 and 2 of the CN A 2Π state. [•] Offset lock of probe laser to a cavity that tracks the bleach laser fluctuations. [Copyright &y& Elsevier]